Question

Balance the following reaction. Choose "blank" if no coefficient is needed.

Answer 1

Answer: $MgCl_2+2AgNO_3\rightarrow 2AgCl+Mg(NO_3)_2$

Explanation: According to law of conservation of mass, the mass can neither be created nor be destroyed. Thus the mass of products must be equal to the mass of reactants.

In order to have same mass on both sides of the chemical equation, the number of atoms of each element must be same in reactants as well as products. Thus the equation is balanced.

$MgCl_2+2AgNO_3\rightarrow 2AgCl+Mg(NO_3)_2$

Answer 2

The  equation  is balanced   as  follows
Mgcl2 +2AgNo3 -->2Agcl +Mg(No3)2
from  equation  above 1 mole of  MgCl2  reacted  with   2  moles  of  AgNo3  to  form 2 moles  of  AgCl2  and  1 mole  of  Mg(NO3)2
when  balancing  equation   the  number  of  atom  of element  should  be the  same  on  each  side  of  equation.