An ornamental of gold having $75\%$ of gold,it is of .............. carat.

An organic compound on analysis gave the following results: $C = 54.5\%$,$O = 36.4\%$,$H = 9.1\%$. The empirical formula of the compound is:

$25 \ g$ of an unknown hydrocarbon upon burning produces $88 \ g$ of $CO_2$ and $9 \ g$ of $H_2O$. This unknown hydrocarbon contains:

Which of the following pairs of species has the same percentage of carbon?

$120 \ g$ of an organic compound that contains only carbon and hydrogen gives $330 \ g$ of $CO_{2}$ and $270 \ g$ of water on complete combustion. The percentage of carbon and hydrogen,respectively,are ...... .

The empirical formula of a compound is $CH_2O$. If its molecular weight is $180$,what is the molecular formula of the compound?