Falling Behind in Studies? Join Our Performance Improvement Batch. Enroll For Free
One of our academic counsellors will contact you within 1 working day.
Click to Chat
1800-1023-196
+91-120-4616500
CART 0
Use Coupon: CART20 and get 20% off on all online Study Material
Welcome User
OR
LOGIN
Complete Your Registration (Step 2 of 2 )
Ques1) The dissociation const of HCN is 5 x 10 - 10 . The pH of the soln prepared by mixing 1.5 moles of HCN and 0.15 moles of KCN in water and making up the total volume to 0.5 dm 3 is (a) 8.302 (b) 7.303 (c) 10.302 (d)9.302 Ques2) 10 ml of an aqeous soln of some strong acid having pH =2 is mixed with 990 ml of the buffer soln with pH = 4. The pH of the resulting soln is (a) 4 (b) 4.10 (c) 3.8 (d)4.25
Hi Tushar, 1) 1/2 lit solution [KCN]=0.15*2=0.3 initial concentration of [HCN]=1.5*2=3 therefore (0.3+x)*x/3=5*10-10 3-x≈3 0.3+x≈0.3 x=5*10-9 pH=log 5*10-9 =9-0.698 =8.302 2) as the acid is added the pH decreases the only option is 3.8 therefore ans is 3.8
Hi Tushar,
1) 1/2 lit solution
[KCN]=0.15*2=0.3
initial concentration of [HCN]=1.5*2=3
therefore
(0.3+x)*x/3=5*10-10 3-x≈3
0.3+x≈0.3
x=5*10-9
pH=log 5*10-9
=9-0.698
=8.302
2) as the acid is added the pH decreases the only option is 3.8
therefore ans is 3.8
Post Question
Dear , Preparing for entrance exams? Register yourself for the free demo class from askiitians.
points won -