Question

Ca + HCl -->
Na + HCl -->
Mg + HCl -->
K + H2O -->
Ba + ... --> H2 ^ + Ba (OH)2

Answer 1

2Na + 2HCl = 2NaCl + H2
Ca + 2HCl= CaCl2 + H2
Mg + 2 HCl = MgCl2 + H2
2K + 2H2O = 2KOH + H2
Ba + 2H2O = Ba (OH) 2 + H2