Question

If all of the chloride in a 5.000-g sample of an unknown metal chloride is precipitated as agcl with 70.90 ml of 0.2010 m agno3 , what is the percentage of chloride in the sample?
a.50.55%
b.10.10%
c.1.425%
d.20.22%
e.None of the above

Answer 1

The percentage of chloride in the sample is 10.11% (answer B)

calculation  and explanation

 step 1: find the moles of  AgNo3

moles = molarity  x volume in liters

volume in liters= 70.90/100=0.709 L

moles=0.2010  x0.709=0.01425 moles which is also moles of cl-

 step 2:find the actual mass of  Cl-

mass = moles x molar mass

= 0.01425 moles x 35.5 g/mol= 0.5059 grams

step 3: find the % mass

actual mass/theoretical mass x 100

0.5059 g/5.000 g  x100 =10.11%