If 22 ml of 0.137m mgcl2 is needed to completely react 15 ml of agno3 solution, what is the molarity of agno3?

The molarity   of AgNO3  is 0.401  M

  calculation

Step 1:  write the chemical equation  for  reaction

MgCl2 + 2AgNO3 →  Mg(No3)2   +  2 AgCl

Step 2: calculate the moles of  MgCl2

moles  =  molarity  x volume  in liters

volume in liters=22/1000=  0.022 L

molarity = 0.137 M   or  0.137 mol/L

moles  is therefore= 0.137 mol/l  x  0.022 L  =3.01 x10^-3  moles

Step 3: use the mole ratio  to determine the moles  of AgNO3

 The mole  ratio  of MgCl2: AgNO3  is 1:2   therefore  the moles of AgNo3  is

= 3.01 x 10^-3 moles x  2/1= 6.02 x 10^-3  moles

Step 4:  find the molarity   of AgNO3

molarity = moles /volume in liters

volume in liters = 15/1000=0.015 L

molarity is therefore =( 6.02 x 10^-3)  /0.015 =  0.401 M

every chemical equation adheres to the law of conservation of mass, which states that matter cannot be created or destroyed. therefore, there must be the same number of atoms of each element on each side of a chemical equation.

the answer is c.the valence of the atoms combine .