Vinegar is a solution of

$(a)$ Complete the following equations:
$(i)$ $CH_4 + 2O_2 \longrightarrow CO_2 + 2H_2O + \text{Heat} + \text{Light}$
$(ii)$ $CH_3COOH + C_2H_5OH \xrightarrow{\text{Acid}} CH_3COOC_2H_5 + H_2O$
$(iii)$ $CH_3CH_2OH \xrightarrow[\text{443 K}]{\text{Conc. } H_2SO_4} CH_2=CH_2 + H_2O$

Explain why washing clothes with hard water is not effective.

How would you name the following compounds?
$(i)$ $CH_{3}-CH_{2}-CH=CH_{2}$
$(ii)$ $CH_{3}-CH_{2}-CH_{2}-C(CH_{3})_{2}-CH_{3}$
$(iii)$ $CH_{3}-CH_{2}-CHO$
$(iv)$ $CH_{3}-CH(OH)-CH_{3}$

Ethanol reacts with sodium and forms two products. These are

Write true or false for the following statement:
Two pairs of electrons are shared between two nitrogen atoms to form a nitrogen molecule.