Salts that are from strong bases and strong acids do not hydrolyze. Salts that are from strong bases and weak acids do hydrolyze, which gives it a pH greater than 7. Salts of weak bases and strong acids do hydrolyze, which gives it a pH less than 7.
a)
A: Copper
B: CuO
C: 
D: $\mathrm{CuCO_3}$
E: $\mathrm{CO_2}$
F: $\mathrm{Cu(NO_3)_2}$
b)
$\mathrm{CuO+ H_2SO_4}\rightarrow \mathrm{CuSO_4 + H_2O}$
c)
$\mathrm{CuCO_3+ 2HNO_3}\rightarrow \mathrm{Cu(NO_3)_2+ CO_2+ H_2O}$
Answer is: cesium sulfide.
Formula for ionic compound is: Cs₂S.
Ionic compound <span>electrically </span>neutral, cesium has charge +1 (2· (+1) = +2) and sulfur has charge -2.
Cesium sulfide is whide powder, soluble in water, pyrophoric in dry air, reductant.
I’m pretty sure the answer is C