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.
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.
D is the best choice. Those percentages, are giving you the information about how concentrated are the solutions. As 0.015 is so concentrated, this solution will damage the structures more quickly