100 mL of 0.20 M Al2(SO4)3 is mixed with 150 mL of 0.10 M Na2SO4 (volumes additive, no reaction). Find the molarity of SO4^2- in the mixture, to two decimals.

JEE Main levelNumerical answerDifficulty 2 of 3mc082

$100 mL$ of $0.20 M$ $Al X_{2} (SO X_{4}) X_{3}$ is mixed with $150 mL$ of $0.10 M$ $Na X_{2} SO X_{4}$ (volumes additive, no reaction). Find the molarity of $SO X_{4} X^{2 -}$ in the mixture, to two decimals.

Numerical answer type, answer in M, tolerance 0.005.

Sulfate from

Al X_{2} (SO X_{4}) X_{3}

= 0.100 x 0.20 x 3 = 0.06 mol; from

Na X_{2} SO X_{4}

= 0.150 x 0.10 = 0.015 mol. Total = 0.075 mol in 0.250 L, giving 0.30 M.