Question

.3. We took small amount of quick lime in a beaker and add water to it. We felt the hot in the

beaker as well as produce a solution which is used for white wash.

i)

Which solution is produced that is used in white wash?

a) Lime stone

b) Quick lime

c) Slaked lime

d) Gypsum

ii)

Which types of chemical reaction is this?

a) Combination and exothermic

b) Decomposition and Exothermic

c) Combination and Endothermic

d) Decomposition and Endothermic

iii)

After applying solution to the wall, a white layer is formed on the walls and gives a shiny

finish. Which compound is formed on the wall?a)

Lime stone

b)

Quick lime

c)

Slaked lime

d)

Gypsum

iv)

There are some common name and chemical name.

Which is correct?

A) Lime stone Calcium Carbonate

B) Slaked lime Calcium Hydroxide

C) lime water

Calcium Hydroxide

D) Quick lime Calcium oxide

Which is correct?

a) Only A

b) A, B and C

c) A, B and D

d) All of the above​

Answer 1

Answer:

Explanation:

a) Combination and exothermic

c) Combination and Endothermic

Calcium hydroxide reacts slowly with the carbon dioxide in air to form a thin layer of calcium carbonate on the walls. Calcium carbonate is formed after two to three days of white washing and gives a shiny finish to the walls.

Answer 2

Answer:

i} c) Slaked lime.

ii} b) Decomposition and Exothermic.

iii} a)  Lime stone.

iv} d) All of the above​.

Explanation:

• White wash is a combination of slaked lime, water and other materials.

• The formation of slaked lime (calcium hydroxide, Ca(OH)₂) when water is added to lime (CaO) is exothermic.

        CaO (s) + H₂O (l) → Ca(OH)₂(s)

• .Calcium hydroxide reacts slowly with the carbon dioxide in air to form a thin layer of calcium carbonate on the walls

              Ca(OH)₂(aq) + CO₂(g) → CaCO₃(s) + H₂O{l}