What is the mole fraction of water in $10 \%$ by weight $(\mathrm{w} / \mathrm{w})$ of aqueous urea solution?

[Given: Molar mass of $\mathrm{H}, \mathrm{O}, \mathrm{C}$ and N are $1,16,12$ and $14 \mathrm{~g} \mathrm{~mol}^{-1}$ respectively.]

The correct order of total number of atoms present in

(A) 2 moles of cyclohexane

(B) 684 g of sucrose

(C) 90.8 L of dihydrogen at STP

is :

Number of moles and number of molecules in 1.4187 L of $\mathrm{SO}_2$ at STP respectively are

The ratio of mass percentage (w/w) of C : H in a hydrocarbon is 12 : 1. It has two carbon atoms. The weight (in g) of CO₂(g) formed when 3.38 g of this hydrocarbon is completely burnt in oxygen is :

(Given : Molar mass in g mol^–1 C : 12, H : 1, O : 16)