If $2 \ g$ of $NaOH$ is dissolved in water to make a $100 \ cm^3$ solution,what is the normality of this solution?

Galena (an ore) is partially oxidized by passing air through it at high temperature. After some time,the passage of air is stopped,but the heating is continued in a closed furnace such that the contents undergo self-reduction. The weight (in $kg$) of $Pb$ produced per $kg$ of $O_2$ consumed is $. . . . .$ (Atomic weights in $g \ mol^{-1}: O = 16, S = 32, Pb = 207$)

When $1 \ dm^{3}$ of $CO_{2}$ gas is passed over hot coke, the volume of the gaseous mixture after the complete reaction at $STP$ becomes $1.4 \ dm^{3}$. The composition of the gaseous mixture at $STP$ is:

What is the percent atom economy if the formula weight of reactants and the formula weight of products are $45 \ u$ and $35 \ u$ respectively (in $\%$)?

The normality of a $1 \ M$ $H_3PO_4$ solution is ........ $N$.

The moles of methane required to produce $81 \ g$ of water after complete combustion is $.... \times 10^{-2} \ mol.$ [nearest integer]