An organic compound contains $C = 38.8\%$,$H = 16\%$ and $N = 45.2\%$. The empirical formula of the compound is:

Two oxides of a metal contain $50\%$ and $40\%$ of the metal,respectively. The formula of the first oxide is $MO$. What is the formula of the second oxide?

Which of the following has the highest percentage of chlorine?

Haemoglobin contains $0.33 \%$ of iron by mass. The molecular mass of haemoglobin is $67200$. The number of iron atoms present in one molecule of haemoglobin is: (Atomic mass of $Fe = 56$)

The empirical formula of an acid is $CH_2O_2$. The probable molecular formula of the acid may be:

When $0.01 \ mol$ of an organic compound containing $60 \%$ carbon was burnt completely,$4.4 \ g$ of $CO_2$ was produced. The molar mass of the compound is $......... \ g \ mol^{-1}$ (Nearest integer).