The given figure shows the set-up to study the reaction between gas X and copper (II) oxide :

Which of the following statements are correct? (Given : Atomic mass of N = 14 u, H = 1 u, O = 16 u, C = 12u)
I. Gas X is a compound of two elements, nitrogen and hydrogen.
II. The number of atoms present in 11.2 L of `N_2` is `6.023 xx 10^(23)`
III. 1 mole of `H_2O` contains 1 mole of oxygen molecules and 2 moles of hydrogen atoms.
IV. `N_2` gas being soluble in water is collected by upward displacement of water.

Options

A. I and II only
B. I and III only
C. II and IV only
D. III and IV only

Answer

A

Explanation

Gas X combines with CuO to give `N_2` and `H_2O`. Thus, it contains nitrogen and hydrogen. 1 mole of `H_2O` contains 1 mole of oxygen atoms and 2 moles of hydrogen atoms.
`N_2` being partially soluble or insoluble in water is collected by downward displacement of water.