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JEE Advanced levelOne or more correct optionsDifficulty 3 of 3mc109

A mixture of $CH X_{4}$ ( $16 g/mol$ ) and $C X_{3} H X_{8}$ ( $44 g/mol$ ) has vapour density $15$ . Choose the correct statement(s). (Molar volume at STP $22.4 L/mol$ .)

AThe mixture contains equal numbers of moles of the two gases.
BThe mass fraction of $CH X_{4}$ is $0.5$ .
CComplete combustion of $1 mol$ of the mixture gives $44.8 L$ of $CO X_{2}$ at STP.
D $22.4 L$ of the mixture at STP weighs $15 g$ .

Answer: A, C

M = 2 x 15 = 30; 16x + 44(1-x) = 30 gives x = 0.5 (A true). Mass fraction of

CH X_{4}

= 8/30 = 0.267 (B false). CO2 per mole of mixture = 0.5 x 1 + 0.5 x 3 = 2 mol = 44.8 L (C true). 22.4 L is one mole = 30 g (D false).

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