Compounds that should not be used as primary standards in titrimetric analysis are :
A. $Na_{2} Cr_{2} O_{7}$
B. Oxalic acid
C. NaOH
D. $FeSO_{4} \cdot 6 H_{2} O$
E. Sodium tetraborate
Choose the most appropriate answer from the options given below:

Question

TestHub · Accepted Answer

The primary standard is a highly pure stable compound with a known exact composition that can be accurately weighed and dissolved to creat a solution of known concentration.
NaOH is hygroscopic and can't be used.
$FeSO_{4} \cdot 6 H_{2} O$ is unstable and can be easily oxidised.
$Na_{2} Cr_{2} O_{7}$ is hygroscopic and can't be used.

Chemistry - Complete d-block Question with Solution | TestHub

Options:

Doubts & Discussion