What is bromine water test?

If the molecular mass of an alkyne is 54, then its molecular formula is _____.

$\mathrm{A}: {\mathrm{C}}_4{\mathrm{H}}_{10} \mathrm{B}: {\mathrm{C}}_4{\mathrm{H}}_6 \mathrm{C}: {\mathrm{C}}_5{\mathrm{H}}_8 \mathrm{D}: {\mathrm{C}}_4{\mathrm{H}}_8$ (Enter your correct answer as $\mathrm{A}, \mathrm{B}, \mathrm{C}$ or $\mathrm{D}$)

The next homologue of ${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}$ is _____.

(A) ${\mathrm{CH}}_3\mathrm{OH}$      (B) ${\mathrm{C}}_3{\mathrm{H}}_7\mathrm{OH}$        (C) ${\mathrm{C}}_4{\mathrm{H}}_9\mathrm{OH}$

Enter your correct answer as A, B or C.

The general molecular formula of alkynes is _____.

(A) ${\mathrm{C}}_{\mathrm{n}}{\mathrm{H}}_{2\mathrm{n}}$                    (B) ${\mathrm{C}}_{\mathrm{n}}{\mathrm{H}}_{2\mathrm{n}+2}$                 (C) ${\mathrm{C}}_{\mathrm{n}}{\mathrm{H}}_{2\mathrm{n}-2}$

Enter your correct answer as A, B or C.