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Moderate

Water Softeners

APCHEM-68ISEJ
Compound $K_{sp}$ at 25$^\circ$C $\hspace{3cm}$
Magnesium carbonate $ 6.82 × 10^{-6}$
Calcium carbonate $ 4.96 × 10^{-9}$
Carbonate A $ 2.58 × 10^{-2}$
Carbonate B $ 6.82 × 10^{-6}$
Carbonate C $ 7.40 × 10^{-10}$
Carbonate D $ 1.46 × 10^{-14}$

$\ $
Consider the data above. Households water softeners work to replace magnesium and calcium ions in tap water with sodium and potassium ions to prevent scale build-up in pipes.

Which of the following substances could also work to prevent carbonate scale build-up?

A

Salt of A.

B

Salt of B.

C

Salt of C.

D

Salt of D.