Write an equilibrium expression for each chemical equation involving

Write an equilibrium expression for each chemical equation involving one or more solid or liquid reac- tants or products.

Part A. HCHO2(aq)+H2O(l)⇌H3O+(aq)+CHO−2(aq)
Use A for [HCHO2], B for [H2O], C for [H3O+], D for [CHO−2].

Part B. CO2−3(aq)+H2O(l)⇌HCO−3(aq)+OH−(aq)
Use A for [CO2−3], B for [H2O], C for [HCO−3], D for [OH−].

Part C

2C(s)+O2(g)⇌2CO(g)
Use A for [C], B for [O2], C for [CO].