Chemistry 2nd Paper MCQ-Jessore Board-2021

1. $\mathrm{A}+\mathrm{Br}_{2}+\mathrm{KOH} \xrightarrow[\text { (1) }]{\Delta} \mathrm{B} \xrightarrow[\text { (2) } 25^{\circ} \mathrm{C}]{\mathrm{NaNO}_{2}+\mathrm{HCl}} \mathrm{R}-\mathrm{H}$
What is the name of the first reaction of the stem?

2. Which one is the weak acid?

3. Which one of the following is a -secondary-standard substance?

4. Which of the following gas has lowest mass of one ml at STP?

5. $\begin{array}{l}\mathrm{Pt}, \mathrm{H}_{2}(\mathrm{~g}) \quad(1 \mathrm{~atm}) / \mathrm{HCl}(1 \mathrm{M}) \| \mathrm{AgNo}_{3} \quad(1 \mathrm{M}) \\ \mathrm{Ag}(\mathrm{s}) \\ \text { At } 25^{\circ} \mathrm{C} \text { temperature, } \mathrm{E}^{\circ} \mathrm{Ag} / \mathrm{Ag}^{-}=-0.80 \mathrm{~V}\end{array}$

What is the emf of the cell of the stem?