How does zinc react with dilute Hydrochloric acid?

How do zinc reacts with air?

What happens when copper oxide reacts with dilute hydrochloric acid?

Metal compound A reacts with dilute hydrochloric acid to produce effervescence. The gas evolved extinguishes a burning candle. Write a balanced chemical equation for the reaction if one of the compounds formed is calcium chloride.

Write balanced chemical eqautions and state symbols for the following reactions . Sodium hydroxide solution ( in water ) reacts with hydrochloric acid solution ( in water ) to produce sodium chloride solution and water.

An unknown aldehyde 'A' on reacting with alkali gives a beta hydroxy aldehyde, which losses water to form an unsaturated aldehyde, but-2-enal. Another aldehyde 'B' undergoes disproportionation reaction in the presence of conc alkali to form products 'C' and 'D'. 'C' is an aryl alcohol with formula C_7H_8O : Name the product, when 'B' reacts with zinc amalgam and hydrochloric acid.