Analytical Chemistry Question 198
Question: For preparing 250 mL of N/20 solution of Mohr ’s salt, the amount of Mohr’s salt needed is
Options:
A) 9.8 g
B) 4.9 g
C) 19.6 g
D) 3.2 g
Show Answer
Answer:
Correct Answer: B
Solution:
[b] The ionic equation for oxidation of Mohr ’s salt is $ F{e^{2+}}\xrightarrow{{}}F{e^{3+}}+{e^{-}} $ Now Eq. of Mohr’s salt $ =\frac{392}{1}=392 $ Strength = Normality $ \times $ Eq. mass $ =\frac{1}{20}\times 392=19.6g/lit $ Thus for preparing 250 ml of N/20 Mohr’s salt solution, Mohr’s salt needed $ =\frac{19.6}{1000}\times 250=4.9g $
BETA
