NEET Questions Solved


Which statement is not correct for hydrogen peroxide ?

(a) Pure H2O2 is fairly stable

(b) It sometimes acts as a reducing agent

(c) It acts as an oxidising agent

(d) Aqueous solution of H2O2 is weakly basic

(d) H2O2 is weak di-basic acid

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Benzene is oxidized by H2O2 in presence of FeSO4 to:

(a) phenol

(b) cyclohexane

(c) benzaldehyde

(d) benzoic acid

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The oxidizing property of H2O2 is best explained by assuming that two oxygen atoms in its molecule are:

(a) bonded differently

(b) bonded similarly

(c) bonded covalently

(d) bonded by hydrogen bonds

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10 volumes of H2O2 has a strength of approximately:

(a) 3%

(b) 30%

(c) 10%

(d) 5%

(a) Percent conc. of H2O21756× volume conc. of H2O2

        =1756×10=3% app.

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From the following statements regarding H2O2, choose the incorrect statement:

(a) It can act only as an oxidising agent

(b) It decomposes on exposure to light

(c) It has to be stored in plastic or wax lined glass bottles in dark

(d) It has to be kept away from dust

(a) H2O2 acts both as reductant and oxidant.

                               O-12          O°2 + 2e                           Reductant                    O-12 + 2e            2O-2                  Oxidant

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H2O2 turns an acidified solution of ........ to orange red.

(a) BaO2

(b) PbO2

(c) Na2O2

(d) TiO2

(d) TiO2 + H2O2           H2TiO4 (orange)

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Which is not true in case of H2O2?

(a) It is more stable in basic solution

(b) It acts as strong oxidising agent in acid and basic solutions

(c) It is decomposed by MnO2

(d) It behaves as reducing agent towards KMnO4

(a) H2O2 is di-basic acid and thus, less stable in basic medium.

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Decmposition of H2O2 is retarded by:

(a) acetanilide

(b) alcohol

(c) H3PO4

(d) all of these

(d) Acetanilide, alcohol, H3PO4 act as negative catalyst for decomposition of H2O2

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Point out the incorrect statement.

(a) Hardness of water depends upon its soap consuming power

(b) Temporary hardness is due to bicarbonates of calcium and magnesium

(c) Permanent hardness is due to soluble sulphates, chlorides and nitrates of Ca and Mg

(d) Permanent hardness can be removed by boiling water

(d) Permanent hardness is the name bacause this type of hardness is not removed by only boiling the water.

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Hydrogen peroxide is now generally prepared on industrial scale by the:

(a) action of H2SO4 on barium peroxide

(b) action of H2SO4 on sodium paraoxide

(c) electrolysis of 50% H2SO4

(d) burning hydrogen in excess of oxygen

(c) Industrial preparation of H2O2:

    (A) By the electrolysis of 50% H2SO4 : 50% H2SO4 solution is electrolysed at 0°C between Pt electrodes. The perdisulphuric acid is formed.                               H2SO4H+ + HSO4-     at Anode;       2HSO4-H2S2O8 + 2e     at cathode; 2H++2e H2     The obtained perdisulphuric acid gives H2O2 on hydrolysis.              H2S2O8 + 2H2O H2O2 + 2H2SO4      This H2O2 is separated by distillation at reduced pressure and thus, 30% solution of H2O2 is obtained.(B) By the auto-oxidation of 2-ehtyle-anthraquinol(Modern Method): Anthraquinol, in a mixture of benzene and n-heptanol on treatement with air gives H2O2 and 2-ethyl-anthroquinone. This 2-ethyl-anthraquinone on hydrogenation gives 2-ethyl-anthraquinol in presence of Pd catalyst.

It is a cyclic process and in it only H2 is consumed, 2 -ethyl-anthraquinone is reobtained during reaction.

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