Question

10L of 2M nacl is subjected to following changes . calculate molarity
1)2 mole nacl is further dissolved
2) 4 moles of agno3 are added to solution
neglect change in volume in both cases
urgent answer​

Answer 1

Answer:

2M NaCl means 2 moles of NaCl in 1L i.e 117g NaCl.

So, for 10L, 1170g of NaCl was added.

1) 2 moles, i.e 117g NaCl is added again. So, new weight is 1170+117 = 1287g

So, molarity is (1287/58.5)/10 = 2.2M

2) AgNO3 + NaCl ---> NaNO3 + AgCl

i.e 1 mole of AgNO3 consumes exactly 1 mole of NaCl. Hence, 4 moles AgNO3 will consume 4 moles NaCl.

Hence, 4×58.5 = 234g NaCl is consumed. So, new weight is 1170-234 = 936g

So, molarity is (936/58.5)/10 = 1.6M