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JEE Advanced levelOne or more correct optionsDifficulty 3 of 3mc110

One mole of $NH X_{3}$ ( $17 g/mol$ ) is $60%$ dissociated by $2 NH X_{3} N X_{2} + 3 H X_{2}$ . Choose the correct statement(s).

AThe total number of moles at equilibrium is $1.6$ .
BThe average molar mass of the mixture is $10.625 g/mol$ .
CThe amount of $H X_{2}$ present is $0.45 mol$ .
DThe mole fraction of $N X_{2}$ is $0.1875$ .

Answer: A, B, D

Per 2 mol

NH X_{3}

reacting, moles rise by 2, so 0.6 mol dissociation gives total = 1 + 0.6 = 1.6 (A true). M = 17/1.6 = 10.625 g/mol (B true). Products:

N X_{2}

= 0.3 mol,

H X_{2}

= 0.9 mol, not 0.45 (C false). Mole fraction of

N X_{2}

= 0.3/1.6 = 0.1875 (D true).

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