Electrolysis and Electrolytes

Q.

A solution of ${\mathrm{CuSO}}_4$ is electrolysed for 10 minutes with a current of 1.5 amperes. what is the mass of copper deposited at the cathode?

Q.

Why is the amount of gas collected in one of the test tubes in Activity 1.7 double of the amount collected in the other? Name this gas.

Q.

What is equivalent weight formula?

Q.

State the difference between acid radical and basic radical

Q.

Define ionic mobility? What is the unit of ionic mobility?

Q. A substance X used for coating iron article is added to a blue solution of a reddish brown metal Y The colour of the solution gets discharged. Identify X and Y and also type of reaction

Q.

On what basis is the discharge potential of ion determined?

Q.

An acidic solution of dichromate is electrolyzed for $8minutes$ using $2A$ current. As per the following equation,

${\mathrm{Cr}}_2{{\mathrm{O}}_7}^{2-}+14{\mathrm{H}}^{+}+6{\mathrm{e}}^{–}\to 2{\mathrm{Cr}}^{3+}++7{\mathrm{H}}_2\mathrm{O}$

The amount of ${\mathrm{Cr}}^{3+}$ obtained was $0.104\mathrm{g}$. The efficiency of the process (in $\%$) is _______(Take: $\mathrm{F}$ = $96000C$, At. mass of chromium = $52$).

Q.

The unit of e.m.f is

1. Joule

2. Joule-coulomb

3. Volt-coulomb

4. Joule/coulomb

Q.

Give reasons for the following :

(a) Electrolysis of molten lead bromide is considered to be a reaction in which oxidation and reduction go side, i.e., a redox reaction.

(b) The blue colour of aqueous copper sulphate fades when it is electrolysed using platinum electrodes.

(c) Lead bromide undergoes electrolytic dissociation in the molten state but is a non- electrolyte in the solid state.

(d) Aluminium is extracted from its oxide by electrolytic reduction and not by conventional reducing agents.

(e) The ratio hydrogen and oxygen formed at the cathode and anode is 2: 1 by volume.

(f) In the electrolysis of acidified water, dilute sulphuric acid is preferred to dilute nitric acid for acidification.

(g) Ammonia is unionised in the gaseous state but in the aqueous solution, it is a weak electrolyte.

(h) A graphite anode is preferred to other inert electrodes during electrolysis of fused lead bromide.

(i) For electroplating with silver, silver nitrate is not used as the electrolyte.

(j) Carbon tetrachloride is a liquid but does not conduct an electrolyte.

(k) Potassium is not extracted by electrolysis of its aqueous salt solution.

Q. Calculate the volume of gas liberated at anode at NTP from the electrolysis of CuSO4 solution by a current of 2 ampere passed for 10 minutes.

1. 0.0696 liters

2. 0.864 liters

3. 1.68 liters

4. 3.45 liters

Q.

What is local action? How it is removed?

Q.

Is $\mathrm{KCl}$ an electrolyte?

Q.

(a) Select the correct answer

The aqueous solution of the compound which contains both ions and molecules is

A. $H_{2}S{O}_4$

B. $HCl$

C. $HN{O}_3$

D. $C{H}_{3}COOH$

(b) Correct the following statement ___.

Lead bromide conducts electricity.

(c) A metal article is to be electroplated with silver. The electrolyte selected is sodium argentocyanide

(i) What kind of salt sodium argentocyanide ?

(ii) Why is it preferred to silver nitrate as an electrolyte ?

(iii) State one condition to ensure that the deposit is smooth, firm and long lasting.

(iv) Write the reaction taking place at the cathode.

(v) Write the reaction taking place at the anode.

(d) Aqueous solution of nickel sulphate contains $N{i}^{2+}$ and $S{O}_4^{2-}$ ions.

(i) Which ion moves towards the cathode ?

(ii) What is the product at the anode ?

Q.

Give reasons for the following:

Electrolysis is considered to be an endothermic reaction.

Q. Define the following terms:
(a) Electrolysis
(b) Electrolyte
(c) Non-electrolyte
(d) Cation and anion

Q.

What is meant by aqueous ? Give an example

Q. The following questions are about electroplating a copper wire with silver.
(a) What ions must be present in the electrolyte?
(b) Of what substance must the anode be made up of?
(c) What will the cathode be made up of?
(d) Write the equation for the reaction which takes place at the cathode.

Q. Which one of the following characteristics of the transition metals is associated with their catalytic activity

1. Paramagnetic behaviour

2. Colour of hydrated ions

3. Variable oxidation states

4. High enthalpy of atomization

Q.

How Do You Find The Cell Constant Experimentally?

Q.

Which of the following salt is a weak electrolyte?

1. NaCl (aq.)

2. CuCl₂ (aq.)

3. Na­₂CO₃

4. CuSO₄(aq)

Q.

Which of the following will not conduct electricity in aqueous solution?

1. Sugar

2. Common salt

3. Copper sulphate

4. None of these

Q.

The electrical resistance of insulators is

1. high

2. low

3. zero

4. infinitely high

Q.

Why is conductivity of dilute $\mathrm{HCl}$ is greater than acetic acid?

Q. Mr. Ramu wants to electroplate his key chain with nickel to prevent rusting. For this electroplating:
(i) Name the electrolyte
(ii) Name the cathode
(iii) Name the anode
(iv) Give the reaction at the cathode
(v) Give the reaction at the anode.

Q.

During the electrolysis of molten sodium chloride, the time required to produce 0.10 mol of chlorine gas using a current of 3 amperes is__

$2{\mathrm{Cl}}^{-}\to {\mathrm{Cl}}_2+2{\mathrm{e}}^{-}$

1. $220$ minutes

2. $330$ minutes

3. $55$ minutes

4. $110$minutes

Q. The graph of pH during the titration of NaOH and HCl

Q. Calculate the pH of N/1000 NaOH solution assuming complete ionisation

Q. a solution of MgCl2 in water has pH 1.<7 2.>7 3.7 4.14.2

Q.

What happens for the concentration of H+ ions on dilution?