Aqua Regia and Its Uses

Q.

Question 33
Write a balanced chemical equation for each of the following reactions and also classify them.

(a) Lead acetate solution is treated with dilute hydrochloric acid to form lead chloride and acetic acid solution.

(b) A piece of sodium metal is added to absolute ethanol to form sodium ethoxide and hydrogen gas.

(c) Iron (III) oxide on heating with carbon monoxide gas reacts to form solid iron and liberates carbon dioxide gas.

(d) Hydrogen sulphide gas reacts with oxygen gas to form solid sulphur and liquid water.

Q.

2 mL each of concentrated HCl, HNO₃ and a mixture of concentrated HCl and concentrated HNO₃ in the ratio of 3: 1 were taken in test tubes labelled as A, B and C. A small piece of metal was put in each test tube. No change occurred in test tubes A and B but the metal got dissolved in test tube C respectively. The metal could be

1. $\mathrm{Al}$

2. $\mathrm{Au}$

3. $\mathrm{Cu}$

4. $\mathrm{Pt}$

Q. What is the concetration of Sulphuric acid in the dilution tank after dilution of Oleum?

1. 98%
2. 97%
3. 95%
4. 92%

Q. Glauber was the first person to prepare HCl gas. What reactants did he use?

1. Nitric acid and chlorine
2. salt and carboxylic acid
3. Sulphuric acid and common salt
4. Water and sulphuric acid

Q.

Acids dissolve most metals. Which special mixture of acids is used to dissolve gold?

1. Aqua Regia

2. Aqua Vitriola

3. Aqua Fortis

4. Aqua Fresca

Q. Gold and Platinum dissolve in aquaregia. Give reason.

Q. Aqua-regia is a mixture of hydrochloric acid and sulphuric acid.

1. True
2. False

Q. Which of the following is used for dissolving gold?

1. Hydrochloric acid
2. Sulphuric acid
3. Nitric acid
4. Aqua regia

Q. Gold cannot be dissolved by any acid. However, it can be dissolved by aqua regia (kingly water) which is a mixture of:

1. mineral water and Iodine
2. nitric and hydrochloric acids
3. water and sulphur
4. alcohol and alum

Q. Noble metals get dissolved in aquaregia the composition of aqua regia is:

1. $3HCl+HN{O}_3$
2. $3HN{O}_3+H_{2}S{O}_4$
3. $HN{O}_3+3h_{2}S{O}_4$
4. $HCl+3HN{O}_3$

Q. <!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> Write the balanced reaction between zinc and hydrochloric acid.

Q. What is aqua regia ?

Q. When conc. $HCl$ is mixed with conc. $HN{O}_3$, the species produced are:

1. $N{O}_2,{Cl}_2,H_{2}O$
2. $NO,{Cl}_2,H_{2}O$
3. $N{O}_2,HOCl$
4. $NOCl,{Cl}_2,H_{2}O$

Q. What happen when?
Gold is dissolved in aqus-regia.

Q. Aqua-regia is:

1. $conc.HN{O}_3+2conc.HCl$
2. $conc.HN{O}_3+3conc.HCl$
3. $conc.HN{O}_3+N{O}_2$
4. $conc.HN{O}_3+2conc.H_{2}S{O}_4$

Q. Aqua regia is a mixture of __________ and ____________ in _____ ratio.

1. nitric acid, hydrochloric acid, 3:1
2. nitric acid, hydrochloric acid, 1:3
3. hydrochloric acid, sulphuric acid, 1:3
4. sulphuric acid, hydrochloric acid, 3:1

Q. The composition of aqua regia is

1. cone. $H_{2}S{O}_4$ and cone. $HCl$ in ratio of $1:3$
2. cone. $HN{O}_3$ and cone. $HCl$ in ratio of $1:3$
3. cone. $HN{O}_3$ and cone. $HCl$ in ratio of $3:1$
4. cone. $H_{2}S{O}_4$ and cone. $HN{O}_3$ in ratio of $3:1$

Q. What is aqua-regia? Name two special metals which are insoluble in common reagents but dissolve in aqua-regia.

Q. What happens when?
Gold is treated with aqua-regia.

Q. What happen when?
Aqua-regia is added to gold.

Q. What is: (a) aqua fortis, (b) aqua regia (c) Fixation of Nitrogen?

Q. Aqua regia is a mixture of ________ and _________ in _________ ratio.