Q 1 :

Which of the following cannot function as an oxidising agent?               [2024]

• ${\mathrm{N}}^{3-}$

   

• ${\mathrm{SO}}_4^{2-}$

   

• ${\mathrm{BrO}}_3^{-}$

   

• ${\mathrm{MnO}}_4^{-}$

   

Q 2 :

Chlorine undergoes disproportionation in alkaline medium as shown below:

${\mathrm{aCl}}_{2\left(\mathrm{g}\right)}+{\mathrm{bOH}}_{\left(\mathrm{aq}\right)}^{-}\to {\mathrm{cClO}}_{\left(\mathrm{aq}\right)}^{-}+{\mathrm{dCl}}_{\left(\mathrm{aq}\right)}^{-}+{\mathrm{eH}}_2{\mathrm{O}}_{\left(\mathrm{l}\right)}$

The values of a, b, c and d in a balanced redox reaction are respectively:

• 2, 2, 1 and 3

   

• 1, 2, 1 and 1

   

• 2, 4, 1 and 3

   

• 3, 4, 4 and 2

   

Q 3 :

In acidic medium, ${\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$ shows oxidizing action as represented in the half reaction:

${\mathrm{Cr}}_2{\mathrm{O}}_7^{2-}+{\mathrm{XH}}^{+}+{\mathrm{Ye}}^{⊝}\to 2\mathrm{A}+{\mathrm{ZH}}_2\mathrm{O}$

X, Y, Z and A, respectively, are                         [2024]

• 8, 6, 4 and ${\mathrm{Cr}}_2{\mathrm{O}}_3$

   

• 14, 7, 6 and ${\mathrm{Cr}}^{3+}$

   

• 8, 4, 6 and ${\mathrm{Cr}}_2{\mathrm{O}}_3$

   

• 14, 6, 7 and ${\mathrm{Cr}}^{3+}$

   

Q 4 :

Thiosulphate reacts differently with iodine and bromine in the reaction given below:

$2{\mathrm{S}}_2{\mathrm{O}}_3^{2-}+{\mathrm{I}}_2\to {\mathrm{S}}_4{\mathrm{O}}_6^{2-}+2{\mathrm{I}}^{-}$

${\mathrm{S}}_2{\mathrm{O}}_3^{2-}+5{\mathrm{Br}}_2+5{\mathrm{H}}_2\mathrm{O}\to 2{\mathrm{SO}}_4^{2-}+4{\mathrm{Br}}^{-}+10{\mathrm{H}}^{+}$

Which of the following statement justifies the above dual behaviour of thiosulphate?              [2024]

• Bromine is a weaker oxidant than iodine

   

• Thiosulphate undergoes oxidation by bromine and reduction by iodine in these reactions

   

• Bromine undergoes oxidation and iodine undergoes reduction in these reactions

   

• Bromine is a stronger oxidant than iodine

   

Q 5 :

$2{\mathrm{MnO}}_4^{-}+b{\mathrm{I}}^{-}+c{\mathrm{H}}_2\mathrm{O}\to x{\mathrm{I}}_2+y{\mathrm{MnO}}_2+z\overline{O}\mathrm{H}$

If the above equation is balanced with integer coefficients, the value of z is ______.             [2024]

Q 6 :

${\mathrm{H}}_2{\mathrm{O}}_2$ acts as a reducing agent in                    [2023]

• ${\mathrm{Na}}_2\mathrm{S}+4{\mathrm{H}}_2{\mathrm{O}}_2\to {\mathrm{Na}}_2{\mathrm{SO}}_4+4{\mathrm{H}}_2\mathrm{O}$

   

• ${\mathrm{Mn}}^{2+}+2{\mathrm{H}}_2{\mathrm{O}}_2\to {\mathrm{MnO}}_2+2{\mathrm{H}}_2\mathrm{O}$

   

• $2{\mathrm{Fe}}^{2+}+2{\mathrm{H}}^{+}+{\mathrm{H}}_2{\mathrm{O}}_2\to 2{\mathrm{Fe}}^{3+}+2{\mathrm{H}}_2\mathrm{O}$

   

• $2\mathrm{NaOCl}+{\mathrm{H}}_2{\mathrm{O}}_2\to 2\mathrm{NaCl}+{\mathrm{H}}_2\mathrm{O}+{\mathrm{O}}_2$

   

Q 7 :

$2{\mathrm{IO}}_3^{-}+x{\mathrm{I}}^{-}+12{\mathrm{H}}^{+}\to 6{\mathrm{I}}_2+6{\mathrm{H}}_2\mathrm{O}$

What is the value of $x$ ?                 [2023]

• 10

   

• 2

   

• 6

   

• 12

   

Q 8 :

Sum of oxidation states of bromine in bromic acid and perbromic acid is ________.              [2023]

Q 9 :

See the following chemical reaction:

${\mathrm{Cr}}_2{\mathrm{O}}_7^{2-}+{\mathrm{XH}}^{+}+6{\mathrm{Fe}}^{2+}\to {\mathrm{YCr}}^{3+}+6{\mathrm{Fe}}^{3+}+{\mathrm{ZH}}_2\mathrm{O}$

The sum of X, Y and Z is _______ .                    [2023]

Q 10 :

Given below are two statements:

Statement I: In the oxalic acid vs. $KMn{O}_4$ (in the presence of dilute $H_{2}S{O}_4$) titration, the solution needs to be heated initially to ${60}^{\mathrm{o}}\mathrm{C}$, but no heating is required in Ferrous ammonium sulphate (FAS) vs.$KMn{O}_4$ titration (in the presence of dilute $H_{2}S{O}_4$).

Statement II: In oxalic acid vs.$KMn{O}_4$ titration, the initial formation of $MnS{O}_4$takes place at high temperature, which then acts as a catalyst for further reaction. In the case of FAS vs.$KMn{O}_4$, heating oxidizes $F{e}^{2+}$ into $F{e}^{3-}$ by oxygen of air and error may be introduced in the experiment.

In the light of the above statements, choose the correct answer from the options given below:                 [2025]

• Statement I is false but Statement II is true

   

• Both Statement I and Statement II are true

   

• Statement I is true but Statement II is false

   

• Both Statement I and Statement II are false