Question

$CaO\left(s\right)+H_{2}O\left(l\right)\to Ca\left(OH{)}_2\right(aq)+heat$

What can be inferred from the above reaction?

(i) $CaO$ is solid.

(ii) $CaO$ is reactive with water.

(iii) $H_{2}O$ is liquid.

(iv) $H_{2}O$ is in vapour state.

(v) $Ca(OH{)}_2$ forms a solution with water

(vi) The reaction is exothermic.

• A. (i), (iii), (iv), (vi)
• B. (i), (ii), (iii), (v), (vi)
• C. (ii), (iii), (v), (iv)
• D. (v), (iv)

Answer 1

The correct option is B

(i), (ii), (iii), (v), (vi)

The following are the conventions used for representing physical states in chemical equation.

(s) represents solid,

(l) represents liquid,

(g) represents gas,

(aq) represents solution in water.

$CaO\left(s\right)+H_{2}O\left(l\right)\to Ca\left(OH{)}_2\right(aq)$ + heat

From the above equation, the following observations can be made.

(a) $CaO$ is solid

(b) $CaO$ and $H_{2}O$ reacts to produce product, So $CaO$ is reactive with water

(c) $H_{2}O$ is in liquid state and not vapour

(d) $Ca(OH{)}_2$ forms a solution with water

(e) Heat is released in the reaction so it's an exothermic reaction.