CaC2 + 2H2O ⟶ C2H2 + Ca(OH)2

How many moles of water are needed to produce 56.8g C2H2?

Amount of moles of water is 4.36 mol

Explanation: M(C2H2) = 2·12.01 + 2·1.008 = 26.036 g/mol

Amount of substance is n= m/M= 56.8 g / 26.036 g/mol= 2.18159 mol

Water is needed 2·2.18 mol = 4.36 mol

the correct option is c.

isotopes refers to different forms of the same element with the same atomic number but different mass number as a result of difference in their neutron numbers. isotopes have different relative atomic mass but share the same chemical properties.