What is the percentage of lead in a lead pencil (in $\%$)?

Which of the following species has the highest mass?

If the density of liquid water is $1.0 \, g \cdot cm^{-3}$ and the density of water vapor is $0.0006 \, g \cdot cm^{-3}$ at $100 \, ^\circ C$ and $1 \, atm$ pressure,then what is the volume occupied by water molecules in $1 \, L$ of steam at the same temperature in $cm^3$?

$4 \ g$ equimolar mixture of $NaOH$ and $Na_{2}CO_{3}$ contains $x \ g$ of $NaOH$ and $y \ g$ of $Na_{2}CO_{3}$. The value of $x$ is $..... \ g$. (Nearest integer)

When water is added to quick lime,the reaction is

Which of the following has the maximum mass?