Solutions Question 359
Question: Which of the following has been arranged in the increasing order of freezing poin'
Options:
A) $ 0.025MKNO_3<0.1MNH_2CSNH_2 $ $ <0.05M,BaCl_2<0.1MNaCl $
B) $ 0.1M,NaCl<0.05M,BaCl_2 $ $ <0.1M,NH_2CSNH_2<0.025M,KNO_3 $
C) $ 0.1M,NH_2CSNH_2<0.1M,NaCl $ $ <0.05M,BaCl_2<0.025M,KNO_3 $
D) $ 0.025M,KNO_3<0.05M,BaCl_2 $ $ <0.1M,NaCl<0.1M,NH_2CSNH_2 $
Show Answer
Answer:
Correct Answer: B
Solution:
Greater is the effective molarity $ ( i\times C ), $ higher the $ \Delta T_{f} $ value and lower the freezing point.
(i) $ 0.1M,NaCl=i\times C=2\times 0.1=0.2 $
(ii) $ 0.05M,BaCl_2=i\times C=3\times 0.05=0.15 $
(iii) $ 0.1M,NH_2CSNH_2=i\times C=1\times 0.1=0.1 $
(iv) $ 0.025M,KNO_3=i\times C=2\times 0.025=0.50 $
Thus, order is (i) < (ii) < (iii) < (iv)
