In H₂-O₂ fuel cell the reaction occurring at cathode is

• 2H₂ (g) + O₂ → 2H₂O(l)

• O₂(g) + 2H₂O(l) + 4e^- → 4OH^-(aq)

• H⁺ +e^- → 1/2H₂

• H⁺(aq) + OH^- → H₂O(l)

Which of the following is incorrect in a galvanic cell?

• Oxidation occurs at anode

• Reduction occurs at cathode

• The electrode at which electrons are gained is called cathode

• The electrode at which electrons are lost is called cathode

A secondary cell is one

• can be recharged

• can be recharged by passing current through it in the same direction

• can be recharged by passing current through it in the opposite direction

• cannot be recharged

The amount of current in Faraday, is required for the reduction of 1 mole of Cr₂O${}_7^{2-}$ ions to Cr³⁺ is

• 1 F

• 2 F

• 6 F

• 4 F

How many Coulombs of electricity are required for the oxidation of one mole of water to dioxygen?

• 9.65 × 10⁴ C

• 1.93 × 10⁴ C

• 1.93 × 10⁵ C

• 19.3 × 10⁵ C

546.

By passing electric current, NaClO₃ is converted in to NaClO₄ according to the following equation

NaClO₃ + H₂O → NaClO₄ + H₂

How many moles of NaClO₄ will be formed when three Faradays of charges is passed through NaClO₃ ?

• 3.0

• 1.5

• 0.75

• 1.0

The final products formed on the addition of KI to copper sulphate solution are :

• K₂SO₄.CuI₂ and I₂

• K₂SO₄.Cu₂I₂ and I₂

• K₂SO₄ and Cu₂O

• K₂SO₄.CuO and I₂

In the electrolysis of aqueous sodium chloride solution, which of the half cell reaction will occur at anode?

• 2H₂O (l) → O₂ + 4H⁺ +4e^-, E${}_{\mathrm{cell}}^{°}= +1.23\mathrm{V}$

• 2H⁺(aq) + e^- → 1/2H_{2,${\mathrm{E}}_{\mathrm{cell}}^{°}= -0.00\mathrm{V}$}

• Na⁺ (aq) + e^- → Na(s) E${}_{\mathrm{cell}}^{°}= -2.71\mathrm{V}$

• Cl^-(aq) → 1/2 Cl₂ + e^-, E${}_{\mathrm{cell}}^{°}=1.36\mathrm{V}$

The standard reduction potential at 298K the following half cell reaction.

Zn²⁺(aq) + 2e^- → Zn(s); E°= -0.762V

Cr³⁺(aq) + 3e^- → Cr(s); E°= -0.740V

2H⁺(aq) + 2e^- → H₂(g); E°= 0.0V

F₂(g) + 2e^- → 2F^-(aq); E°= 2.87V

Which of the following is strongest reducing agent?

• Zn(s)

• Cr(s)

• H₂(g)

• F₂(g)

Which of the following ions can be replaced by H⁺ ions when H₂ gas is bubbled through the solutions containing these ions ?

• Li

• Ba²⁺

• Cu²⁺

• Be²⁺