In the standardization of $Na_2S_2O_3$ using $K_2Cr_2O_7$ by iodometry,the equivalent weight of $K_2Cr_2O_7$ is

$K_2Cr_2O_7$ is preferred to $Na_2Cr_2O_7$ for use in volumetric analysis as a primary standard because

Identify the incorrect statements regarding primary standard of titrimetric analysis.
$(A)$ It should be purely available in dry form.
$(B)$ It should not undergo chemical change in air.
$(C)$ It should be hygroscopic and should react with another chemical instantaneously and stoichiometrically.
$(D)$ It should be readily soluble in water.
$(E)$ $KMnO_4$ and $NaOH$ can be used as primary standard.
Choose the correct answer from the options given below:

Which of the following reagents is not used in qualitative and quantitative chemical analysis?

$10 \, mL$ of concentrated $HCl$ were diluted to $1 \, L$. $20 \, mL$ of this diluted solution required $25 \, mL$ of $0.1 \, N$ sodium hydroxide solution for complete neutralization. The normality of the concentrated hydrochloric acid will be:

The ammonia evolved from the treatment of $0.30 \, g$ of an organic compound for the estimation of nitrogen was passed in $100 \, mL$ of $0.1 \, M$ sulphuric acid. The excess of acid required $20 \, mL$ of $0.5 \, M$ sodium hydroxide solution for complete neutralization. The organic compound is: