Chemical Equations

Q. Calcium hydroxide + Carbon dioxide → Calcium carbonate + Water

The balanced chemical equation for the following word equation is:

1. ${\text{Ca(OH)}}_2\text{(aq)}+{\text{CO}}_2\text{(g)}\to {\text{CaCO}}_3\text{(aq)}+{\text{H}}_2\text{O}\text{(l)}$
2. ${\text{Ca(OH)}}_2\text{(aq)}+2{\text{CO}}_2\text{(g)}\to 2{\text{CaCO}}_3\text{(aq)}+{\text{H}}_2\text{O(l)}$
3. $2{\text{Ca(OH)}}_2\text{(aq)}+{\text{CO}}_2\text{(g)}\to 2{\text{CaCO}}_3\text{(aq)}+2{\text{H}}_2\text{O(l)}$
4. $2{\text{Ca(OH)}}_2\text{(aq)}+{\text{CO}}_2\text{(g)}\to {\text{CaCO}}_3\text{(aq)}+2{\text{H}}_2\text{O(l)}$

Q. $2\mathrm{Mg}\left(s\right)+O_2\left(g\right)\to 2\mathrm{MgO}\left(s\right)$
In the given equation, magnesium (Mg) is a .

1. reactant
2. product
3. catalyst

Q. The arrow pointing downwards $(\downarrow )$ along with a product represents a gaseous product, whereas the arrow pointing upwards $(\uparrow )$ represents the precipitate in a reaction.

1. True
2. False

Q. $C+O_2\to C{O}_2$

In the reaction given above, $C{O}_2$ is on the reactant side.

1. False
2. True

Q.

What are the reactants in the following reactions?

$KOH\left(aq\right)+HN{O}_3\left(aq\right)\to H_{2}O\left(l\right)+KN{O}_3\left(aq\right)$

1. $H_{2}O$ , $KN{O}_3$

2. $HN{O}_3$ , $H_{2}O$

3. $KN{O}_3$ , $KOH$

4. $KOH$ , $HN{O}_3$