Attempt the question, check the explanation, and continue with similar questions to build confidence before exams.
CO2 + H2O → H2CO3
NaOH + HCl → NaCl + H2O
Fe + HCl → FeCl2 + H2
H2 + O2 → H2O
Continue with nearby questions to strengthen the same chapter concept while you still have the context fresh in mind.