Answer:
B. Q > K precipitate will form
Explanation:
The reaction is;
Ba(NO3)2(aq) + Na2CO3(aq) ------> BaCO3(s) + 2NaNO3(aq)
Hence the reaction could form a precipitate of BaCO3.
Number of moles of carbonate ions = 50/1000 * 0.10 M = 5 * 10^-3 moles
Number of moles of Barium ions = 20/1000 * 0.10 M = 2 * 10^-3 moles
Total volume after reaction = 20ml + 50ml = 70 ml or 0.07 L
Molarity Barium ions = 5 * 10^-3 moles/ 0.07 L = 0.07 M
Molarity carbonate ions = 2 * 10^-3 moles/ 0.07 L =0.03 M
Q = [Ba^2+] [CO3^2-] = 0.07 * 0.03 = 2.1 * 10^-3
But K = 2.58 × 10
^−
9
We can clearly see that Q>K therefore precipitate will form
