Answer :
The concentration in mEq of a 2.75 * 10^{-2} M SO_4^{2-} solution is 55 mEq(a), because each mole of sulfate ions produces 2 equivalents, and after multiplying by the valency (2) and converting to milliequivalents, the result is 55 mEq/L.
The concentration (in mEq) of a solution containing 2.75 * 10^{-2} M SO_4^{2-} ions can be calculated by considering that sulfate ion (SO_4^{2-}) has a charge of 2-. This means that each mole of sulfate ions will produce 2 equivalents. To find the concentration in milliequivalents (mEq), the molarity (M) of the ions needs to be multiplied by the valency and then by 1000 (to convert from equivalents to milliequivalents).
Calculation:
Concentration in mEq = 2.75 * 10^{-2} M * 2 eq/mol * 1000 mEq/eq = 55 mEq/L
Therefore, the correct answer is a. 55 mEq.
