x g of Ag was dissolved in nitric acid and the solution was treated with excess of NaCl when 2.87g of AgCl was precipitated.the value of x is

Asked by  | 21st Mar, 2013, 10:22: AM

Expert Answer:

Ag (Coin) + NaCl --> AgCl 

The molecular weight of AgCl is M(agcl)= 143.32 g.mol-1

You have m (AgCl)= 2.87 g of AgCl at the end so that means you have:

m(agcl)/M(AgCl) = 2.87g/143.32g.mol-1 =  0.020 moles of AgCl or n(agcl).

Since we know the reaction was complete, it means you had 0.020 moles of silver in the coin: n(ag)=n(agcl).
So, silver was 0.20 moles.
Now the molecular weight of silver is:
M(ag) = 107.868 g.mol-1

So your weight of silver in the coin was:

m(ag)=n(ag)xM(ag)= 0.20 mol x 107.868 g.mol-1

So m(ag) = 21.57 g

Answered by  | 25th Mar, 2013, 06:32: AM

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