The Properties Of Nitric Acid Research Essay

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Ordinal number? ? ? ? ? ? ? ? ? ? ? ? ? ? ? . .Introduction? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 1. Plan? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 3? ? ? ? ? ? ? ? ? ? Outline of method? ? ? ? ? ? ? ? ? ? ? Reactions. Consequences: ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 7? ? ? ? ? ? ? ? ? ? ? ? Acidic belongingss? ? ? ? ? ? ? ? ? ? ? ? Oxidising belongingss? ? ? ? ? ? ? ? ? ? ? ? Reducing properties.. Discussion: ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 9? ? ? ? ? ? ? ? ? ? ? Evaluation. Bibliography? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 14. Chemical equipment? s and lists. ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 15Introduction: An probe on the belongingss of Nitrous acid. ? ? ? ? ? ? ? ? ? ? ? The survey

under this probe was concerned with the acerb base and oxidation-reduction reactions

of Nitrous acid. Azotic acid is a weak acid of ka 4.7 ten 10-4

formed from the reaction: NaNo2 ( aq ) ? + HCl ( aq ) & # 174 ;

HNO2 ( aq ) ? +NaCl ( aq ) . ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ( azotic

acid ) ? ? ? ? ? ? ? ? ? ? ? Related

surveies have shown that a pale bluish solution is formed from this reactions a

consequence of an unstable oxide N2O3 and that HNO2

is an unstable compound because it decomposes really fast at room temperature. It

was hence used up instantly after being made from its component? s

reactants, Sodium nitrite and Hydrochloric acid. The instability of the compound means that it

disproportionates at standard room temperature.HNO2 ( aq ) ? & # 8212 ; & # 8211 ; HNO3 ( aq ) ?

+NO ( g ) ? ? ? ? ? ? ? ? ? ? ? ?

? ? ? ? ? ? ( azotic acid ) ? ? ? ? ? ? ( nitrogen monoxide ) ? ? ? ? ? ? ? ? ? ? ? Disproportionation

occurs when one of the reactant molecule in a reaction forms two merchandises, one

merchandise which is obtained by the oxidization of the reactant molecule and the

other by decrease. To restrict this consequence, Le Chatelier? s rule applied that

chilling the system will switch the equilibrium to the exothermal way of

the equation to understate the temperature lessening. In this instance an ice bath was

used to drive the reaction towards the left-hand side. This necessarily bounds

the dispropornation reactions.To demonstrate the acidic belongingss of Azotic

acid, the three criterion trials were set.Acid?

+ ? base/alkali? ? ? & # 174 ; ? ? ? Salt + waterAcid?

+ ? Metal? ? ? & # 174 ; ? ? ? ? ? Metal Salt? ? + HydrogenAcid? +

Carbonate? ? ? ? & # 174 ; ? ? ? ? Salt?

+ ? Carbondioxide? + ?

WaterThe oxidation-reduction reactions involve decreases and

oxidizations. To oppugn the position that HNO2 behaved as either a

reducing agent, oxidizer or both, scientific theories and experiments were applied

based on the fact that it displays the features set by the followers

criterions As a reduction

agent it reduces another coinage by donating negatrons to it. As an oxidising

agent it oxidises another coinage by taking negatrons from it. To practically show the acerb base, oxidation-reduction

reactions of HNO2 the undermentioned reagents were used based on factors

concerned with cost, handiness and the nature of their reactions.1Reagents: Acidic reactions Magnesium solid Sodium hydrated oxide solution Sodium Carbonate solidReduction reactions Bromine H2O Pottasuim manganate ( VII ) solution Sodium bichromate ( VI ) solutionOxidation reactions Pottasium iodide solution Iron ( II ) sulphate solution Sulphur dioxide solutionIn all the instances, the anticlockwise regulation

was applied to do anticipations on whether a reaction took topographic point and possible

results of the merchandises. Appropriate trials were carried out in some of the

reactions to separate formation of merchandises if any from that of a mixture of

the reactants. Prior to doing an aqueous solution of HNO2,

consideration were given to the little graduated table research lab process and the

following safety safeguards: & # 183 ;

Use standard research lab concentrations of 2M. & # 183 ;

Wear research lab coats and goggles. & # 183 ;

Avoid inhaling toxic N monoxide gas ( usage

fume closet ) 2 Plan:

Preparation of Nitrous acid? An aqueous

solution of 2M HNO2 was made from cold acidified aqueous solution of

Na nitrite from the equation.NaNo2 ( aq ) ? + HCl ( aq ) ? ?

& # 174 ; ? HNO2 ( aq ) ? + ?

NaCl ( aq ) Calculations: Gram molecules of NaNo2 and HCL, ratio 1:1 Amount needed = 100cm3 of 2M HNO2 Amount of HCl = 50cm3 of 2M HCl? ? ? ? ? ? ? ? ? ? 50 x 2? ? ? = 0.1 moles? ? ? ? ? ? ? ? ? ? ? 1000Moles of NaNo2 = 0.1 moles Mass = 0.1?

ten? ( RMM? 69g ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? =6.9g? ? ? ? ? ? ? ? ? ? ? 6.9g

of NaNo2 makes up 50cm3 of 2M solution.Outline

of method: & # 183 ;

Set up a conelike flask placed into an ice bath. & # 183 ;

Weigh 6.9g of solid NaNo2 and fade out

in 50cm3 of distilled H2O. & # 183 ;

Pour solution into conelike flask

inside ice bath. & # 183 ;

Cool down to a temperature scope of ( 0? 5 ) 0C in ice bath. & # 183 ;

Add 50cm3 of 2M HCl to conical flask & # 183 ;

Topographic point setup in fume closet & # 183 ;

Carry out trials with the conelike flask placed in

ice bath.Procedure: 3cm3 of Azotic acid was

used to respond in all instances to 3cm3 and little parts of reactant

solutions and solids. A tabular array of consequences was set up to summarize observations

of coloring material alterations, exhausts and consequence of tests.3 Chemical reactions: Acid? base? ? ? ? ? ? ? ? ? ? ? Magnesium? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? A metal plus an acid will ensue in the

formation of a metal salt and H gas as shown in the equation.2HNO2 ( aq ) ? ? + ? ? ? Mg ( s ) ? ? & # 174 ; ? Mg ( NO2 ) 2

( aq ) ? + ?

H2 ( g ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ( magnesium nitrite ) Prediction: ? An exothermal reaction will happen as at that place

will be effervescence of H. Magnesium solid dissolves. ? ? ? ? ? ? ? ? ? ? ? Sodium hydrated oxide? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? This

acid? basal reaction should bring forth salt and H2O as a consequence of

neutralization.HNO2 ( aq ) ?

+ ? NaOH ( aq ) ? & # 174 ; ? NaNo2 ( aq ) ? + ? ? Water

( cubic decimeter ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ( Na

nitrite ) Prediction: A

neutralisation reaction should happen bring forthing a salt. A impersonal pH should

bespeak a green coloring material utilizing a cosmopolitan indicator. ? ? ? ? ? ? ? ? ? ? ? Sodium Carbonate? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? A

reaction affecting carbonates produces a metal salt, H2O and carbondioxide

gas.HNO2 ( aq ) + NaCO3 ( s ) ? & # 174 ;

NaNo2 ( aq ) +CO2 ( g ) + H2O ( cubic decimeter ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ( sodium nitrite ) Prediction: The

chemical equation suggests effervescence of the carbondioxide gas and a impersonal

pH for the metal salt formation of a green coloring material utilizing the universal

index. Solution should turn cloudy with limewater ( CaOH2 )

bring forthing white precipitates of CaCO3 ( s ) ? ? ? ? ? ? ? ? ? ? ? CO2 ( g )

+ CaOH2 ( aq ) & # 174 ;

CaCO3 ( s ) + H2O ( cubic decimeter ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ( Ca

carbonate ) 4 Oxidation Pottasuim Iodide? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? The

anticlockwise regulation applies that I – ( aq ) will be oxidised to I2 ( s )

harmonizing to the equation: ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

Tocopherol I2 ( s ) ?

+2e & # 8212 ; – ? 2I- ( aq ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? +

0.54V 2HNO2 ( aq ) + 2H+ ( aq ) + 2e

& # 8212 ; & # 8211 ; ? ? 2NO ( g ) + H2O ( cubic decimeter ) ? ? ? ? ? ? ? ? ? ? ? ? ? +0.99VFull equation 2HNO2 ( aq ) + 2H+ ( aq ) +2I- ( aq ) ? & # 174 ;

I2 ( s ) + 2NO ( g ) + 2H2O ( cubic decimeter ) Prediction:

Iodine will be formed and its presence detected by a blueblack coloring material from a

amylum index. Brown fumes given off, due to NO2 gas formation

from? 2NO ( g ) + O2 ( g ) ? & # 174 ;

2NO2 ( g ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ( air ) ? ? ? ? ? ? ( brown

exhausts ) Iron ( II ) sulfate? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? E Fe3+ ( aq ) ? + vitamin E & # 8212 ; – Fe2+ ( aq ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? +0.76V HNO2 ( aq ) + H+ ( aq ) + vitamin E & # 8212 ; –

NO ( g ) + H2O ( cubic decimeter ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? +0.99VFull equation HNO2 ( aq ) + H+ ( aq ) + Fe2+ ( aq )

& # 174 ; Fe3+ ( aq )

+ NO ( g ) + H2O ( cubic decimeter ) Prediction: ? Fe3+ will be produced as brown

precipitates of Fe ( OH ) 3 ( s ) , when the solution mixture is reacted with

Na hydrated oxide. Fe3+ ( aq ) + OH- ( aq ) & # 174 ; Fe ( OH ) 3 ( s ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ( brown ppt ) ? ? ? ? ? ? ? ? ? ? ? Sulphur dioxide? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? E SO42- ( aq ) + 4H+ ( aq )

+2e & # 8212 ; – ? SO2 ( aq ) +2H2O ( cubic decimeter ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

+0.17V 2HNO2 ( aq ) + 2H+ ( aq ) +2e

& # 8212 ; & # 8211 ; 2NO ( g ) +2H2O ( cubic decimeter ) ? ? ? ? ? ? ? ? ? ? ? +0.99V? Full equation 2HNO2 ( aq ) + SO2 ( aq ) +2H+

( aq ) + 2H2O ( cubic decimeter ) & # 174 ;

SO42- ( aq ) + 4H+ ( aq ) + 2NO ( g ) + 2H2O ( cubic decimeter ) Prediction:

SO42- ( aq ) will be produced as white precipitates of BaSO4 ( s ) ,

when the solution mixture is reacted with Barium Chloride. ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Ba2+ ( aq ) + SO42- ( aq )

& # 174 ; BaSO4 ( s ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ( white ppt ) 5 Decrease? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Bromine H2O? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? E NO3- ( aq ) + 3H+ ( aq )

+2e & # 8212 ; – ? ? HNO2 ( aq ) + H2O ( cubic decimeter ) ? ? ? ? ? ? ? ? ? ? ? ? +0.94V Br2 ( cubic decimeter ) ?

+ ? 2e & # 8212 ; & # 8211 ; ? 2Br- ( aq ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? +1.07VFull equation HNO2 ( aq ) +Br2 ( cubic decimeter ) + H2O ( cubic decimeter )

& # 174 ; NO3- ( aq )

+ 3H+ ( aq ) ? +2Br- ( aq ) Prediction: Bromine

H2O should be reduced to bromide ions and the positive trial of creamy

precipitates of Ag bromide should be observed after adding a part of

AgNO3 ( aq ) to the solution. Br- ( aq ) + ? Ag+ ( aq ) & # 174 ;

AgBr ( s ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ( creamy ppt ) . ? ? ? ? ? ? ? ? ? ? ? Pottasuim manganate ( VII ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? E 5NO3- ( aq ) +15H+ ( aq )

+10e & # 8212 ; & # 8211 ; 5HNO2 ( aq ) + 5H2O ( cubic decimeter ) ? ? ? ? ? ? ? ? +0.94V 2MnO42- ( aq ) + 16H+ ( aq )

+10e & # 8212 ; 2Mn2+ ( aq ) + 8H2O ( cubic decimeter ) ? ? ? ? ? ? ? ? +1.52VFull equation 5HNO2 ( aq )

+ 2MnO42- ( aq ) + 16H+ ( aq ) +10e & # 8212 ; 5NO3- ( aq )

+2Mn2+ ( aq ) +15H+ ( aq ) +8H2O ( cubic decimeter ) .Prediction:

Purple Mn7+ ( aq ) harmonizing to the equation will be reduced to

colourless Mn2+ ( aq ) ? ? ? ? ? ? ? ? ? ? ? Sodium

bichromate ( VI ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? E NO3- ( aq )

+ 3H+ ( aq ) + vitamin E & # 8212 ; – HNO2 ( aq ) + H2O ( cubic decimeter ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? +0.94V Cr2O72- ( aq )

+ 14H+ ( aq ) + vitamin E & # 8212 ; 2Cr3+ ( aq ) + 7H2O ( cubic decimeter ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? +1.33VFull

equation HNO2 ( aq )

+Cr2O7 2- ( aq ) +14H+ ( aq ) + H2O ( cubic decimeter ) & # 174 ; 2Cr3+ ( aq )

+NO3- ( aq ) +3H+ ( aq ) + 7H2O ( cubic decimeter ) Prediction:

The anticlockwise regulation applies that Nitrous acid in this instance will cut down

orange Cr6+ ( aq ) to green Cr3+ ( aq ) . 6Results

showing belongingss of Azotic Acid. Acidic

belongingss? Reagents Predictions Observations Magnesium Solid Exothermic reaction should happen as

H gas is given off. Magnesium solid dissolves. Vigorous reaction. Effervescence of H2 ( g )

foliages test tubing warm. Brown gas produced. Sodium hydroxide solution A neutralisation reaction in this instance should

consequence to a impersonal pH. Colour should turn green with a cosmopolitan index. Colourless

+indicator ( violet ) + HNO2 ( green ) Sodium carbonate solid The metal salt NaNo2 will be formed

with a impersonal pH. Carbon dioxide and H2O produced. CO2 presence

detected utilizing limewater to bring forth white CaCO3 ( s ) Colourless+ index ( bluish ) + HNO2 ( green ) Effervescence of CO2 ( g ) With limewater white ppt produced. Carbonate dissolves. Decisions: The reactions occurred as awaited

bring forthing conclusive sets of consequences. With the Mg, a & # 8217 ; pop & # 8217 ; trial was

carried out to corroborate H2 gas produced. Brown fumes given off by the

system was unexplained in the anticipations, but a qualitative ground was looked

on further in the treatment. A alteration in pH during the NaOH ( aq ) trial clearly

indicated the formation of a salt, which had a impersonal pH. The Carbonate

reaction and trial demonstrated that the metal salt NaNo2 was formed

P >

and C dioxide evolved.Oxidising belongingss? Reagents Predictions Observations Pottasuim Iodide I2 will be formed and the presence

demonstrated by a blueblack coloring material with amylum. Probable brown exhausts of NO oxidization. ? Foaming. Colourless

+HNO2 ( black ppt ) +

amylum ( bluishblack ) brown

exhausts IronIISulphate Fe3+ ( aq ) produces as brown ppt of

Fe ( OH ) 3 ( s ) when the mixture is reacted with NaOH ( aq ) Probable brown exhausts of NO oxidization. Brown fumes Clear solution +HNO2 ( darkgreen ppt ) + NaOH ( brown ppt ) Sulphur dioxide Mixture of acid and SO2 reacts to

give White precipitates of BaSO4 ( s ) with

a? ? ? mixture of BaCl2 Mixture +BaCl2 & # 174 ; white ppt. Decisions: HNO2

has the inclination to move as an oxidizer and oxidised the above reactants,

approved by the observation and standard trials carried out. A elaborate

account of the mechanisms observed was given in the discussion.Reducing belongingss? Reagents Predictions Observations? Bromine

H2O Br2 ( cubic decimeter ) reduces to Br- ( aq ) Br- ( aq ) + Ag+ ( aq ) & # 174 ; AgBr ( s ) creamy ppt Brown

+HNO2 ( clear ) +

AgNo3 ( aq ) creamy ppt. ? Pottasuim maganate ( VII ) Purple Mn7+ reduces to colourless Mn2+ Colour alteration Purple +HNO2 ( colourless ) Sodium bichromate ( VI ) ? Anticlockwise regulation applies that Orange Cr6+ ( aq )

reduces to greenCr3+ Orange+HNO2 ( green ) Decision: Conclusive grounds from the above trials suggests

that HNO2 ( aq ) has the inclination to act as a cut downing specie.8 Discussion? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Using

the anticlockwise regulation had clearly with in consequence suggested the mechanism in

which the reactions occurred. A much negative E value increases the inclination

for HNO2 to move as a reduction agent, and a more positive E value

allows the inclination to move as an oxidising agent. The ground to which why these

chemical reactions occur will be discussed in relation to Gibbs energy. The

following information summarises the findings of the HNO2 reactions. As an Acid, ?

the consequences were obtained as predicted. Effervescence produced

by the reaction with Mg, warmed the trial tubing as it was an exothermal

reaction. Brown exhausts were nevertheless produced from this reaction without being

predicted. The exothermal nature of this reaction could account for the

oxidization of NO ( g ) . A high assurance degree in consequences was confirmed with the

? dad? trial for H gas and with limewater in the carbonate reaction to

cheque for CO2 ( g ) . Significantly the carbonate reaction had outlined

HNO2 to be a stronger acid compared to carbonic acid as it had

protonated the carbonate ion to let go of carbondioxide. As an Oxidising agent, the E chart

illustrates as to why the observations of the reactions fit into the anticipation

form. In this instance HNO2 has more inclination to accept elactrons so

has a more positive Tocopherol than that of the reactants.Pottasuim iodide,

ironIIsulphate and sulfur dioxide were oxidised by HNO2 which

itself was reduced by release of NO2 fumes.When pottasuim iodide was

used, the initial black precipitates seen was a consequence of I formation

which was confirmed with amylum to give the typical blueblack coloring material. HNO2 ( aq ) + H+ ( aq ) + 2I- ( aq )

& # 174 ; I2 ( s )

+ NO ( g ) + H2O ( cubic decimeter ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ( bluishblack? ? ? ? ?

( oxidised to brown exhausts of NO2 ) ? with amylum ) Nitrous acid reduced to nitrogen monoxide Iodide oxidised to Iodine. ( oxidization no.increase

+1 ) The

reaction with ironIIsulphate produced a calcium hydroxide green coloured solution. After the

add-on of NaoH, the brown ppt. Produced was a positive trial for the presence

of Fe3+ ( aq ) . HNO2 ( aq ) +H+ ( aq ) + Fe2+ ( aq ) & # 174 ; Fe3+ ( aq )

+ NO ( g ) +H2O ( cubic decimeter ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ( green ) ? ?

( brown with NaOH ) Nitrous acid reduced to nitrogen monoxide Fe2+ oxidised to Fe3+ ( oxidization

no. increase +1 ) The

Sulphur dioxide reaction shows the formation of white ppt. of sulphate ions

after the add-on of Ba chloride solution. 2HNO2 ( aq ) +2H+ ( aq ) + SO2 ( aq ) +2H2O ( cubic decimeter ) & # 174 ; SO42- ( aq )

+4H+ ( aq ) +2NO ( g ) +2H2O ( cubic decimeter ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ( white ppt with BaSO4 ) Nitrous acid reduced to Nitrogen monoxide S4+ oxidised to S6+ ( oxidization

no. increase +2 ) ? ? ? ? ? ? ? ? ? ? ? In

all the equations the oxidization figure of nitrogen inHNO2 ( +3 ) had

been reduced to ( +2 ) in NO and so hence HNO2? is an oxidising agent. 9 As a Reducing agent the E charts

illustrates that from the anticlockwise regulation that Nitrous acid is oxidised to

nitrate and the corresponding reactants reduced as it has a more negative Tocopherol

value and more inclination to donate negatrons. The brown Br H2O was reduced to colourless

Br- in solution. Br- reacted with Ag+ to organize

AgBr ( s ) . HNO2 ( aq ) + Br2 ( cubic decimeter ) + H2O ( cubic decimeter )

& # 174 ; NO3- ( aq )

+ 2Br- ( aq ) + 3H+ ( aq ) . ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ( creamy

ppt with AgNO3 ) HNO2 oxidised? to NO3- Br2 reduced to Br-

( oxidization no. diminish? 1 ) When

KMnO4 ( aq ) was reacted. A color alteration from purple to

colourless? was shown the coloring material alteration

showed that Mn2+ was formed. 5HNO2 ( aq ) + 2MnO42- ( aq )

+16H+ ( aq ) & # 174 ;

5NO3- ( aq ) + 15H+ ( aq ) +2Mn2+ ( aq ) +

4H2O ( cubic decimeter ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ( purple ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ( colourless ) HNO2 oxidised to NO3- Mn7+ reduced to Mn2+ ( oxidization

no. diminish? 5 ) The Na2Cr2O7

reaction showed that Cr3+ was formed, the coloring material alteration from

orange to green was observed. HNO2 ( aq )

+Cr2O72- ( aq ) +14H+ ( aq ) +H2O ( cubic decimeter ) & # 174 ; 2Cr3+ ( aq )

+NO3- ( aq ) +3H+ ( aq ) +7H2O ( cubic decimeter ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ( orange ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ( green ) HNO2

oxidised to NO3- Cr6+

reduced to Cr3+ ( oxidization no.decrease? 3 ) ? ? ? ? ? ? ? ? ? ? ? In all the above equations, Azotic

acid was oxidised to nitrate ion. The

oxidization figure of N in HNO2 ( +3 ) increased to ( +5 ) in NO3- . HNO2? is a cut downing agent. ? ? ? ? ? ? ? ? ? ? ? Related surveies as to why the oxidation-reduction

reactions of Azotic acid occur could be viewed by the information alterations in the

reactions. The survey by the American scientist Willard Gibbs reviews that the

relationship between the entire information of a chemical reaction and the electromotive

force of the corresponding cell is? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? & # 8710 ; S sum

= -zFEcell? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? T As

chemists are merely concerned with the reaction inside the trial tubing excepting

the milieus the Gibbs free energy?

& # 8710 ; G was used and expressed as? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? & # 8710 ; G = -T & # 8710 ; S total10For a

alteration, in a reaction to hold taken topographic point of its ain agreement, For a self-generated

alteration? & # 8710 ; S

must be positive. It hence follows that for a self-generated

alteration? & # 8710 ; Gmust be negative. A

reaction is normally described as traveling to completion if kc =1010 or

greater ; this corresponds to a value of & # 8710 ; G of

about? 60kJmol-1 or a greater negative value. ? & # 8710 ; G = & # 8710 ; G

merchandises? & # 8211 ; & # 8710 ; G

reactantsIn the

Reduction reaction Bromine

H2O HNO2 ( aq )

+Br2 ( cubic decimeter ) +H2O ( cubic decimeter ) & # 174 ;

NO3- ( aq ) +3H+ ( aq ) +2Br- ( aq ) ( -37.2 ) ? ? ? ? ? ? ? ? ?

0.0? ? ( -237.2 ) ? ? ? ? ?

( 111.3 ) ? ? ? ? ? ? ? ? ? ? 0.0? ? ? ? ? ? ?

( -104.0 ) ? & # 8710 ; G = [ 2 ( -104.0 ) ? ( 113.0 ) ] ?

[ ( -237.2 ) – ( 37.2 ) ] ? ? = -44.9 kJmol-1? & # 8710 ; S entire =-44.9 ten 1000? = +150Jmol-1k-1? , therefore the reaction is executable. ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

-298Pottasuim

maganate ( VII ) 5HNO2 ( aq )

+ 2MnO42- ( aq ) + 16H+ ( aq ) + 5H2O ( cubic decimeter ) & # 174 ; 5NO3- ( aq )

+ 2Mn2+ ( aq ) +15H+ ( aq ) +8H2O ( cubic decimeter ) ( -37.2 ) ? ? ? ? ? ? ? ? ? ? ? ? ( -447.2 ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 0.0? ? ? ? ?

( -237.2 ) ? ? ? ? ? ? ? ? ( -111.3 ) ? ? ? ? ? ? ? ( -228.0 ) ? ? ? ? ? ? 0.0? ? ? ? ? ? ?

( -237.2 ) ? & # 8710 ; G? = [ 5 ( -111.3 ) +2 ( -228.0 ) +8 ( -237.2 ) ] ? [ 5 ( -37.2 ) + 2 ( -447.2 ) +

8 ( -237.2 ) ] ? ? = -643.6 kJmol-1? ? & # 8710 ; S total = -643.6 ten 1000

= +2159 Jmol-1k-1, therefore the reaction is executable. ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? -298Sodium

bichromate ( VI ) HNO2 ( aq )

+ Cr2O72- ( aq ) +14H+ ( aq ) +H2O ( cubic decimeter )

& # 174 ; 2Cr3+ ( aq )

+NO3- ( aq ) +3H+ ( aq ) +7H2O ( cubic decimeter ) ( -37.2 ) ? ? ? ?

( -1301.2 ) ? ? ? ? ? ? ? ? 0.0? ? ? ? ? ( -237.2 ) ? ? ? ? ? ? ( -204.9 ) ? ? ? ? ? ? ( -111.3 ) ? ? ? ? ? ? 0.0? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ( -237.2 ) ? & # 8710 ; G = [ 7 ( -237.2 ) ? 111.3 +

2 ( -204.9 ) ] ? [ -37.2? 1301.2? 237.2 ] ? = -605.5 kJmol-1? & # 8710 ; S total = -605.5 ten 1000

= +2031.9 Jmol-1k-1, therefore the reaction is executable. ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? -29811 In the

Oxidation reactionPottasuim

iodide HNO2 ( aq )

+ 2H+ ( aq ) + 2I- ( aq ) & # 174 ; I2 ( s )

+ 2NO ( g ) +2H2O ( cubic decimeter ) ( -37.2 ) ? ? ? ? ? ? ? ? ? ? ? 0.0? ? ? ? ? ? ( -51.6 ) ? ? ? ? ? 0.0? ? ? ? ? ? ( 86.6 ) ? ? ? ? ? ? ( -237.2 ) ? & # 8710 ; G = [ 2 ( -237.2 ) =2 ( 86.6 ) ] ?

[ 2 ( -51.6 ) + 2 ( -37.2 ) ] ? = -123.6 kJmol-1? & # 8710 ; S total = -123.6 ten 1000

= +414.7 Jmol-1K-1, therefore the reaction is executable. ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? -298Iron ( II ) sulfate HNO2 ( aq ) + Fe2+ ( aq ) + H+ ( aq )

& # 174 ; Fe3+ ( aq )

+NO ( g ) +H2O ( cubic decimeter ) ( -37.2 ) ? ? ? ? ? ? ? ? ? ? ? ? ( -78.9 ) ? ? ? ? 0.0? ? ? ? ? ? ? ? ? ? ? ? ? ? ( -4.6 ) ? ? ? ? ?

( 86.6 ) ? ? ? ? ( -237.2 ) ? & # 8710 ; G =

[ 86.6? 4.6? 237.2 ] ? [ -78.9? 37.2 ] = -39.1 kJmol-1? & # 8710 ; S sum

= -39.1 ten 1000 = +131.2 Jmol-1k-1, therefore the

reaction is executable. ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? -298? The

Sulphur dioxide information was unavailable.The pH of 2M Azotic acidKa = [ H+ ( aq ) ] eq [ NO2- ( aq ) ] combining weight? ? ? ? ? ? ? ? ? ? ? ? Ka value = 4.7 x10-4? ? ? ? ? ? ? ? ? ? ? ? ? ? [ HNO2 ( aq ) ] eqSince really small HNO2? dissociates [ HNO2 ( aq ) ] aq = [ HNO2 ( aq ) ] initialKc = ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

[ H+ ( aq ) ] eq x [ H+ ( aq ) ] ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? { HNO2 ( aq ) ] combining weight? ? ? ? ? ? ? 4.7

x10-4 = [ H+ ( aq ) ] 2? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 2.0? ? ? ? ? ? ? ? ? ? & # 1062 ; 9.4 x10-4

= [ H+ ( aq ) ] , ? ? ? ? ? ? ? ? ? ? ? 3.0

ten 10-2 = [ H+ ( aq ) ] . pH = -log10 [ 3.0 x 10-2 ] ? ? ? = 1.5 12 Azotic acid is a weak acid and will merely ionise

small in H2O. The Kc value is hence little due to uncomplete ionisation.

The? & # 8710 ; G, E and & # 8710 ; S sum

values have demonstrated that the reactions were feasible.EVALUATION: ? The

technique and processs applied to the trial was of good steps, as most of

the anticipations were observed. To raise the assurance degrees in the consequences if

this probe was to be repeated a larger scope of reactants would be

used. As with the acidic belongingss, a buffer solution of Nitrous acid and

Na nitrite could be set up to detect the buffering consequence of the acid, and

its reactions with oxides to look for a form. In the oxidation-reduction reactions,

V compounds could be used as the variable oxidization Numberss of V

are easy distinguished in simple reactions by the colorss produced by its

ions.13 Bibliography? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Relevant

mentions were obtained from the undermentioned sources.Nuffield Advanced Science Chemistry pupil book ( 3rd edition ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ( longman

publishing houses ) Chemistry in context ( 3rd edition ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? P.W.

Atkins? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? M.J.

Glugston? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? M.J.

Fazer? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Beam

Jones. ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Advanced Chemistry ( first edition ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Michael

Clugston? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Rosalind

Flemming. ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ( Oxford

Publishers ) 14Chemical

Equipment? s and lists. Equipments? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Conic Flask Spatula Ice bath Thermometer

Mass balance PipetteSolutions and Materials Distilled H2O Iron ( II ) sulphate Pottasuim iodide Pottasuim manganate Sodium bichromate Magnesium Solid Hydrochloric acid Sodium nitrite Sodium hydrated oxide Sodium carbonate Sulphur dioxide Bromine H2O? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Indicators? Universal

index Starch Silver nitrite Barium Chloride. 15