Answer:
Step-by-step explanation:
a) Zinc has a charge of plus 2 and hydrogen gas is H₂ so HCl would have a two in front to balance the equation
b) All have charges of plus one
c) Copper has a charge of plus two (given) and it needs two chlorine atoms to become stable and hence to balance the whole equation, you would need two moles of sodium hydroxide and sodium chloride