JEE Main 2022 (Online) 26th July Evening Shift | Redox Reactions Question 28 | Chemistry

JEE Main 2022 (Online) 26th July Evening Shift

MCQ (Single Correct Answer)

-1

Given below are two statements: one is labelled as Assertion $$\mathbf{A}$$ and the other is labelled as Reason $$\mathbf{R}$$.

Assertion A: Phenolphthalein is a $$\mathrm{pH}$$ dependent indicator, remains colourless in acidic solution and gives pink colour in basic medium.

Reason R: Phenolphthalein is a weak acid. It doesn't dissociate in basic medium.

In the light of the above statements, choose the most appropriate answer from the options given below.

Both $$\mathbf{A}$$ and $$\mathbf{R}$$ are true and $$\mathbf{R}$$ is the correct explanation of $$\mathbf{A}$$.

Both $$\mathbf{A}$$ and $$\mathbf{R}$$ are true but $$\mathbf{R}$$ is NOT the correct explanation of $$\mathbf{A}$$.

A is true but R is false.

A is false but R is true.

JEE Main 2022 (Online) 26th July Morning Shift

MCQ (Single Correct Answer)

-1

Which of the given reactions is not an example of disproportionation reaction?

$$2 \mathrm{H}_{2} \mathrm{O}_{2} \rightarrow 2 \mathrm{H}_{2} \mathrm{O}+\mathrm{O}_{2}$$

$$2 \mathrm{NO}_{2}+\mathrm{H}_{2} \mathrm{O} \rightarrow \mathrm{HNO}_{3}+\mathrm{HNO}_{2}$$

$$\mathrm{MnO}_{4}^{-}+4 \mathrm{H}^{+}+3 \mathrm{e}^{-} \rightarrow \mathrm{MnO}_{2}+2 \mathrm{H}_{2} \mathrm{O}$$

$$3 \mathrm{MnO}_{4}^{2-}+4 \mathrm{H}^{+} \rightarrow 2 \mathrm{MnO}_{4}^{-}+\mathrm{MnO}_{2}+2 \mathrm{H}_{2} \mathrm{O}$$

JEE Main 2022 (Online) 26th June Evening Shift

MCQ (Single Correct Answer)

-1

Which one of the following is an example of disproportionation reaction ?

$$3MnO_4^{2 - } + 4{H^ + } \to 2MnO_4^ - + Mn{O_2} + 2{H_2}O$$

$$MnO_4^ - + 4{H^ + } + 4{e^ - } \to Mn{O_2} + 2{H_2}O$$

$$10{I^ - } + 2MnO_4^ - + 16{H^ + } \to 2M{n^{2 + }} + 8{H_2}O + 5{I_2}$$

$$8MnO_4^ - + 3{S_2}O_3^{2 - } + {H_2}O \to 8Mn{O_2} + 6SO_4^{2 - } + 2O{H^ - }$$

JEE Main 2021 (Online) 27th July Morning Shift

MCQ (Single Correct Answer)

-1

The oxidation states of 'P' in H₄P₂O₇, H₄P₂O₅ and H₄P₂O₆, respectively, are :

7, 5 and 6

5, 4 and 3

5, 3 and 4

6, 4 and 5

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