You have 75.0 mL of a 2.50 M solution of Na₂CrO₄(aq).You also have 125 mL of a 2.01 M solution of AgNO₃(aq).Calculate the concentration of CrO₄²^- after the two solutions are mixed together.

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Quizplus · Accepted Answer

To find the concentration of $CrO_4^{2-}$ after mixing, first calculate the moles of $CrO_4^{2-}$ initially present in the Na$_2$CrO$_4$ solution. Moles of $CrO_4^{2-}$ = volume (L) × molarity = 0.075 L × 2.50 M = 0.1875 moles. When mixed with AgNO$_3$, no reaction occurs that would consume $CrO_4^{2-}$, so the total volume of the solution becomes 75.0 mL + 125 mL = 200 mL or 0.2 L. The concentration of $CrO_4^{2-}$ after mixing is then moles/volume = 0.1875 moles / 0.2 L = 0.9375 M, which rounds to 0.938 M, but given the context of the question implying a reaction that would consume $CrO_4^{2-}$, the correct interpretation involves a mistake in the reaction assumption. The correct answer should consider the dilution effect without the reaction, but the provided choices and explanation seem to mismatch typical chemical reactions between these compounds, suggesting a possible error in the interpretation of the chemical reaction or in the calculation steps provided. The correct approach involves calculating the final concentration based on dilution and reaction stoichiometry, but without clear reaction details, the precise answer hinges on assumed details not fully provided in the question.

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