Kerala Board Solutions for Chapter: Redox Reactions and Rate of Chemical Reactions, Exercise 2: Let us assess

Some chemical equations are given below.
$\mathrm{C}+{\mathrm{O}}_2\to {\mathrm{CO}}_2$
${\mathrm{CH}}_4+2{\mathrm{O}}_2\to {\mathrm{CO}}_2+2{\mathrm{H}}_2\mathrm{O}$
${\mathrm{N}}_2+{\mathrm{O}}_2\to \mathrm{NO}$
${\mathrm{CaCO}}_3\to \mathrm{CaO}+{\mathrm{CO}}_2$
${\mathrm{H}}_2+{\mathrm{l}}_2\to \mathrm{Hl}$
$\mathrm{Fe}+\mathrm{HCl}\to {\mathrm{FeCl}}_2+{\mathrm{H}}_2$
${\mathrm{CO}}_2+\mathrm{C}\to \mathrm{CO}$
a) Which of these are balanced equations?
b) Balance the unbalanced equations.
c) Which among these are redox reactions?

The chemical reaction between marble and dilute$\mathrm{HCl}$ is given.
${\mathrm{CaCO}}_3+2\mathrm{HCl}\to {\mathrm{CaCl}}_2+{\mathrm{H}}_2\mathrm{O}+{\mathrm{CO}}_2$
Which gas is formed here? How can you identify this gas?

The chemical reaction between marble and dilute$\mathrm{HCl}$ is given.

${\mathrm{CaCO}}_3+2\mathrm{HCl}\to {\mathrm{CaCl}}_2+{\mathrm{H}}_2\mathrm{O}+{\mathrm{CO}}_2$

Suggest any two ways you would choose to increase the rate of this chemical reaction. Explain the reason.

Sulphur pieces do not react with cold concentrated nitric acid. But sulphur powder reacts. Explain the reason why the rate of chemical reaction is increased here?

Sulphur pieces do not react with cold concentrated nitric acid. But sulphur powder reacts.

Suppose you want to increase the rate of reaction again. Which way you would choose? Give reason.

Small amounts of phosphoric acid is usually added to hydrogen peroxide to prevent its decomposition. What is the function of phosphoric acid here?

Small amounts of phosphoric acid is usually added to hydrogen peroxide to prevent its decomposition. By which name are these type of substances known?

Small amounts of phosphoric acid is usually added to hydrogen peroxide to prevent its decomposition. Which substance would you add to increase the rate of decomposition of hydrogen peroxide?