MCQ
A gaseous hydrocarbon gives upon combustion $0.72\, g$ of water and $3.08\, g$ of $CO_2.$ The empirical formula of the hydrocarbon is :
- A$C_2H_4$
- B$C_3H_4$
- C$C_6H_5$
- ✓$C_7H_8$
$\therefore 0.72 \mathrm{g} \mathrm{H}_{2} \mathrm{O}$ contain $0.08 \mathrm{g} \mathrm{H}$
$44 \mathrm{g} \mathrm{CO}_{2}$ contain $12 \mathrm{g} \mathrm{C}$
$\therefore 3.08 \mathrm{g} \mathrm{CO}_{2}$ contain $0.84 \mathrm{g} \mathrm{C}$
$C: H=\frac{0.84}{12}: \frac{0.08}{1}=0.07: 0.08=7: 8$
$\therefore$ Empirical formula $=\mathrm{C}_{7} \mathrm{H}_{8}$
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Statement $I:$ In the titration between strong acid and weak base methyl orange is suitable as an indicator.
Statement $II:$ For titration of acetic acid with $\mathrm{NaOH}$ phenolphthalein is not a suitable indicator.
In the light of the above statements, choose the most appropriate answer from the options given below: