Reaction between which of the following two reactants will produce hydrogen gas?

Which of the following slows down the reaction rate?

In which one of the following reactions, the maximum quantity of H₂ gas is produced by the decomposition of 1 g of compound by H₂O/O₂?

Which one of the following does not form oxide on reaction with oxygen?

Which one of the following processes involves chemical reaction?

Which one of the following is not an oxidation reaction?