Electrochemistry

In the refining ofsilver by electrolytic method, what will be the weight of 100 g Ag anode if 5A current is passed for hours ? The purity of silver anode is 95% by weight.

• 42.91 g

• 57.59 g

• 13.16 g

• 36.38 g

Salt bridge contains :

• calomel

• corrosive sublimate

• agar-agar paste

• H₂O

Assertion : In electrolysis, the quantity of electricity needed for depositing 1 mole of silver is different from that required for 1 mole of copper.

Reason : The molecular weights of silver and copper are different.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false.

• If both assertion and reason are false

What is the amount of chlorine liberated when 2A of current is passed for 60 minutes in an aqueous solution of NaCl?

• 2.507 g

• 1.364 g

• 2.648 g

• 3.469 g

Which of the following electrolytic solutions has the least specific conductance ?

• 0.02 N

• 0.2 N

• 2 N

• 0.002 N

The hydrogen electrode is dipped in a solution of pH = 3 at 25°C .The potential of the cell would be ,

(the value of 2.303 RT/F is 0.059 V)

• 0.177 V

• 0.087 V

• -0.177 V

• 0.059 V

Which cell will measure standard electrode potential of copper electrode?

• ${\text{Pt}}_{\left(s\right)}\left|H_{2(g, 0.1 bar)}\right| H_{(a.q., 1M)}^{+}\left|\right| C{u}_{(a.q.,1M)}^{2+}|C{u}_{\left(s\right)}$

• ${\text{Pt}}_{\left(s\right)}| H_{2(g, 1bar)}|H_{(a.q.,1 M)}^{+}\left|\right| C{u}_{(a.q., 1M)}^{2+}| C{u}_{\left(s\right)}$

• ${\text{Pt}}_{\left(s\right)}| H_{2(g, 1bar) }|H_{(a.q., 1M)}^{+}\left|\right|C{u}_{(a.q., 1M)}^{2+}|C{u}_{\left(s\right)}$

• ${\text{Pt}}_{\left(s\right)}| H_{2(g, 1 bar)}|H_{(a.q., 0.1M)}^{+}\left|\right|C{u}_{(a.q., 1M)}^{}|C{u}_{\left(s\right)}$

Assertion : Zinc displaces copper from copper sulphate solution.

Reason : The E${}_{298 \mathrm{K}}^{°}$ of Zn is -0.76 V and that of Cu is +0.34 V.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

Assertion : Pure iron when heated in dry air is covered with a layer of rust.

Reason : Rust has the composition Fe₃O₂.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false

• If both assertion and reason are false

Assertion : Al becomes passive in conc. HNO_3.

Reason: Conc. HNO₄, has no action on aluminium metal.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

•  If both assertion and reason are false.