Methylation of $10 \ g$ of benzene gave $9.2 \ g$ of toluene. Calculate the percentage yield of toluene $......$. (Nearest integer)

The solution of sulphuric acid contains $80\%$ by weight $H_2SO_4$. The specific gravity of this solution is $1.71$. Its normality is about:

How many grams of $NaOH$ are required to neutralize $12.2 \ g$ of benzoic acid (in $g$)?

Magnetite can be reduced with $CO$ to yield iron metal and carbon dioxide. Calculate the mass of magnetite (in $kg$) needed to obtain $4 \ kg$ of iron if the process is $80 \%$ efficient. [Atomic weight of $Fe$ and $O$ are $56 \ g$ and $16 \ g$, respectively]

What is the mass in $g$ of $70\%$ $H_2SO_4$ required for the neutralization of $1$ mole of $NaOH$?

The weight of a residue obtained by heating $2.76 \, g$ of silver carbonate is......$g$