Zinc Ion

Q.

Give an example of a chemical reaction which is characterised by the evolution of a gas.

Q.

Give the characteristic test for ${\mathrm{CO}}_2$ gas.

Q.

Name a hydroxide which is highly soluble in water?

Q.

What is Solubility Test?

Q.

In the given reaction, 3.9 g of benzene on nitration gives 4.92 g of nitrobenzene. The percentage yield of nitrobenzene in the above reaction is _____%. (Round off to the Nearest Integer). (Given atomic mass: C: 12.0 u, H: 1.0 u, O: 16.0 u, N: 14.0 u)

Q.

What is the $\mathrm{pH}$ of$0.1M$$\mathrm{NaOH}$solution?

Q.

On adding a drop of barium chloride solution to an aqueous solution of sodium sulfite, a white precipitate is obtained.

(a) Write a balanced chemical equation of the reaction involved

(b) What other names can be given to this precipitation reaction?

(c) On adding dilute hydrochloric acid to the reaction mixture, white precipitate disappears. Why?

Q. Write the equation for the following reaction:
Zinc oxide is treated with sodium hydroxide solution.

Q.

Write the balanced equation for reduction of iron (III) oxide by carbon monoxide?

Q.

A metal X forms a salt $XS{O}_4$. The salt $XS{O}_4$ forms a clear solution in water which reacts with sodium hydroxide solution to form a blue precipitate Y. Metal X is used in making electric wires and alloys like brass.

(a) What do you think metal X could be ?

(b) Write the name, formula and colour of salt $XS{O}_4$

(c) What is the blue precipitate Y ?

(d) Write a chemical equation of the reaction which takes place when salt $XS{O}_4$ reacts with sodium hydroxide solution. Give the state symbols of all the reactants and products which occur in the above equation.

Q. State what will you observe when ammonium hydroxide solution is added to copper sulphate in excess.

Q.

How would you distinguish between dilute HCl and dilute HNO3 by addition of only one solution.

Q. Sodium hydroxide solution is added first in a small quantity, then in excess to the aqueous salt solutions of copper (II) sulphate, zinc nitrate, lead nitrate, calcium chloride and iron (III) sulphate. Copy the following table and write the colour of the precipitate in (i) to (v) and the nature of the precipitate (soluble or insoluble) in (vi) to (x).

Aqueous salt Solution	Colour of precipitate when NaOH is added in a small quantity	Nature of precipitate (soluble or insoluble) when NaOH is added in excess
Copper (II) sulphate Zinc nitrate Lead nitrate Calcium chloride Iron (III) sulphate	(i) (ii) (iii) (iv) (v)	(vi) (vii) (viii) (ix) (x)

Q.

Distinguish by adding : Sodium hydroxide solution and ammonium hydroxide solution to
(a) Calcium salt solution and lead salt solution.
(b) Lead salt solution and zinc salt solution.
(c) Copper salt solution and ferrous salt solution.
(d) Fe(II) salt solution and Fe(III) salt solution.
(e) Ferrous nitrate and lead nitrate

Q.

A white solid A when heated with sodium hydroxide solution gives a pungent gas B which turns red litmus paper blue. The solid when dissolved in dilute nitric acid is treated with Silver nitrate solution to give white precipitate C, which is soluble in ammonia.

(A) What are the substance A, B, and C?

(B) Write an equation from the direct changes taking place in the experiments.

Q. (a) Sodium hydroxide solution is added to solution A. A white precipitate is formed which is insoluble in excess sodium hydroxide solution. Name the metal ion present in solution A.
(b) When ammonium hydroxide is added to solution B, a pale blue precipitate is formed. This pale blue precipitate dissolves in excess ammonium hydroxide to give an inky blue solution. Name the cation present in solution B. What is the probable colour of solution B?

Q.

Tell me all colours of chemical solutions like H2SO4, NASO4 etc. With their chemical formula

Q. Why is temperature above 200C is not used in laboratory preparation of HCL

Q. Aluminium reacts with oxygen to form aluminium oxide. How many moles of oxygen required to react completely with $0.5$ moles of aliminium?

1. $\frac{2}{3}\text{moles}$
2. $\frac{3}{8}\text{moles}$
3. $\frac{2}{5}\text{moles}$
4. $\frac{7}{8}\text{moles}$

Q.

Give an example for neutral oxide.

Q.

Calculate the percentage of nitrogen and oxygen in ammonium nitrate.[Relative molecular mass of molecular nitrate is 80 , H= 1, N =14, O= 16].

Q.

Write the balanced chemical equation for the reaction of Zinc with Potassium hydroxide solution?

Q.

In a reaction between zinc and hydrochloric acid, the changes accompanying a reaction are:

1. Evolution of gas and heat

2. Evolution of steam

3. Formation of precipitate

4. Formation of dazzling white light

Q. On adding dilute ammonia solution to a colourless solution of a salt, a white gelatinous precipitate appears. This precipitate however dissolves on addition of excess of ammonia solution. Identify (Choose from Na, Al, Zn, Pb, Fe)
(a) which metal salt solution was used?
(b) what is the formula of the white gelatinous precipitate obtained?

Q.

The ratio of the molar amounts of $H_{2}S$ needed to precipitate the metal ions from $20mL$ each of 1M $Cd(N{O}_3{)}_2$ and 0.5 M $CuS{O}_4$ is

1. 1 : 1
2. 2 : 1
3. 1 : 2
4. Indefinite

Q.

A black color solid which on reaction with dilute sulphuric acid forms a blue colored solution is:

1. Carbon

2. Manganese (IV) oxide

3. Lead (II) oxide

4. Copper (II) oxide

Q.

A metal salt (M) on reacting with sodium hydroxide forms sodium sulphate and a gelatinous white precipitate of a metal hydroxide. The precipitate is soluble in excess of sodium hydroxide. Identify M.

1. Calcium

2. Magnesium

3. Zinc

4. Iron

Q.

The reaction of zinc with hot concentrated caustic alkalis involve the liberation of

1. hydrogen chloride gas.

2. carbon dioxide gas.

3. hydrogen gas.

4. oxygen gas.

Q.

Choose the correct option given to distinguish between Zinc sulphate solution and zinc chloride solution

1. Add barium chloride solution to each of the solutions. The solution in which a white precipitate is formed is Zinc chloride and the other in which no effect is Zinc sulphate

2. Add ammonium hydroxide solution to each of the solutions. The solution in which a white precipitate is formed is Zinc chloride and the other in which no effect is Zinc sulphate

3. Add barium chloride solution to each of the solutions. The solution in which a white precipitate is formed is Zinc sulphate and the other in which no effect is Zinc chloride

4. Add sodium hydroxide solution to each of the solutions. The solution in which a white precipitate is formed is Zinc sulphate and the other in which no effect is Zinc chloride

5. Add sodium hydroxide solution to each of the solutions. The solution in which a white precipitate is formed is Zinc chloride and the other in which no effect is Zinc sulphate

6. Add ammonium hydroxide solution to each of the solutions. The solution in which a white precipitate is formed is Zinc sulphate and the other in which no effect is Zinc chloride

Q.

Which two solutions will give a white precipitate when treated with dilute nitric acid followed by silver nitrate solution?

1. Copper nitrate and Lead nitrate

2. Iron(II) sulphate and Magnesium sulphate

3. Iron(II) sulphate and Iron(III) chloride

4. Iron(III) chloride and Zinc chloride

5. Lead nitrate and Zinc chloride