Q 1 :

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R.

Assertion A: An aqueous solution of KOH when used for volumetric analysis, its concentration should be checked before the use.

Reason R: On aging, KOH solution absorbs atmospheric ${\mathrm{CO}}_2$.

In the light of the above statements, choose the correct answer from the options given below:                    [2023]

• (A) is correct but (R) is not correct

   

• (A) is not correct but (R) is correct

   

• Both (A) and (R) are correct but (R) is not the correct explanation of (A)

   

• Both (A) and (R) are correct and (R) is the correct explanation of (A)

   

Q 2 :

${\mathrm{KMnO}}_4$ is titrated with ferrous ammonium sulphate hexahydrate in presence of dilute ${\mathrm{H}}_2{\mathrm{SO}}_4$. Number of water molecules produced for 2 molecules of ${\mathrm{KMnO}}_4$ is ________.           [2023]

Q 3 :

$x$ mg of pure $\mathrm{HCl}$ was used to make an aqueous solution. 25.0 mL of 0.1 M $\mathrm{Ba}{\left(\mathrm{OH}\right)}_2$ solution is used when the $\mathrm{HCl}$ solution was titrated against it. The numerical value of $x$ is __________ $\times {10}^{-1}$ (Nearest integer).

Given: Molar mass of $\mathrm{HCl}$ and $\mathrm{Ba}{\left(\mathrm{OH}\right)}_2$ are 36.5 and $171.0{\text{\hspace{0.05em}g mol}}^{-1}$ respectively.                 [2026]

Q 4 :

Identify the correct statements :

A. Hydrated salts can be used as primary standard.
B. Primary standard should not undergo any reaction with air.
C. Reactions of primary standard with another substance should be instantaneous and stoichiometric.
D. Primary standard should not be soluble in water.
E. Primary standard should have low relative molar mass.

Choose the correct answer from the options given below :         [2026]

• A, B and C Only

   

• A, B, C and E Only

   

• A, B and E Only

   

• D and E Only

   

Q 5 :

Number of molecules of $H_{2}S{O}_4$ present in $100\text{\hspace{0.05em}mL}$ of $0.02M$ $H_{2}S{O}_4$ (assume no dissociation) solution is _______

• $12.044\times {10}^{20}$ molecules

   

• $6.022\times {10}^{23}$ molecules

   

• $1\times {10}^{23}$ molecules

   

• $12.044\times {10}^{23}$ molecules

   

Q 6 :

Assertion: $H_{3}P{O}_4+2NaOH\to N{a}_{2}HP{O}_4+2H_{2}O$

Eq. wt of $H_{3}P{O}_4$ in above reaction is 49

Reason: In all reactions $H_{3}P{O}_4$ is a dibasic acid

• A is True, R is true R is correct explanation of A

   

• A is True, R is True R is not correct explanation of A

   

• A is True, R is false

   

• A is false, R is True