Which of the following is a primary standard substance?

Options

A. `H_(2)SO_(4)`
B. `K_Cr_(O_(7))`
C. `KBrO_`
D. `KOH`

Answer

2

Explanation

`K_(2)Cr_(2)O_(7)` is used as a primary standard in volumetric analysis (titration) because it does not react with or absorb the components of the atmosphere, such water vapor, oxygen and carbon dioxide.