Extraction of Metals Towards the Top of the Reactivity Series

Q.

Which of the following metals are extracted by the electrolysis of their molten chlorides?
(a) Na and Hg (b) Hg and Mg (c) Na and Mg (d) Cu and Fe

Q. How to extract sodium from its ore?

Q.

How does the method used for extracting a metal from its ore depend on the metal's position in the reactivity series? Explain with examples.

Q. What are the chemical effects of electric current?

Q.

In an electrolytic tank, aluminium metal is being extracted by the electrolysis of molten aluminium oxide using carbon electrodes. It is observed that one of the carbon electrodes is gradually burnt away and has to be replaced.
(a) Which carbon electrode (cathode or anode) is burnt away?
(b) Why is this carbon electrode burnt away?

Q. in a electrolytic tank aluminium metal is being extracted by d electrolysis of molten aluminium oxide using carbon electrodes.Ot is observed that one of the carbon electrodes is gradually burnt away and has to be replaced
i)Which carbon electrode is burnt away and Why?
Briefly explain

Q.

Zinc oxide can be reduced to zinc by using carbon monoxide, but aluminium oxide cannot be reduced by a reducing agent. Give reason.

Q.

Explain giving one example, how highly reactive metals (which are high up in the reactivity series) are extracted.

Q.

On electrolysis of aqueous $NaCl$, Hydrogen gas is produced at which electrode?

Q. The metals like sodium, potassium, and aluminium can be obtained from their ores by:

1. Electrolysis
2. Heating in presence of air
3. Heating in absence of air
4. Heating below its melting point

Q.

The two metals which are extracted by means of electrolytic reduction of their molten salt are:
(a) magnesium and manganese (b) iron and aluminium
(c) zinc and magnesium (d) magnesium and aluminium

Q. The following is a sketch of an electrolytic cell used in the extraction of aluminium:
Figure

(a) What is the substance of which the electrodes A and B are made?
(b) At which electrode (A or B) is the aluminium formed?
(c) What are the two aluminium compounds in the electrolyte C?
(d) Why is it necessary for electrode B to be continuously replaced?

Q.

Most reactive element among the following is:

1. Hydrogen

2. Calcium

3. Sodium

4. Copper

Q.

Explain briefly how the activity series helps to study the reduction of metallic oxides.

Q.

Question 18
Which of the following metals are obtained by electrolysis of their chlorides in molten state?
(i) $\text{Na}$
(ii) $\text{Ca}$
(iii) $\text{Fe}$
(iv) $\text{Cu}$

(a) (i) and (iv)
(b) (iii) and (iv)
(c) (i) and (iii)
(d) (i) and (ii)

Q. Which of the following elements are present at the top of the reactivity series?

1. Sodium
2. Potassium
3. Calcium
4. Zinc

Q. The metals like Na, K, Ca, Al are obtained by:

1. roasting
2. electrolytic reduction
3. calcination
4. simple heating

Q. From the given table, identify the set of metals that cannot be extracted from their ores using carbon reduction method.

1. Set - A
2. Set - B
3. Set - C
4. Both Sets - B & C

Q. Which of the following metals are obtained by electrolysis of their chlorides in molten state?
(i) $Na$
(ii) $Ca$
(iii) $Fe$
(iv) $Cu$

1. (iii) and (iv)
2. (i) and (iv)
3. (i) and (iii)
4. (i) and (ii)

Q.

From the given table, identify the set of metals cannot be obtained by carbon reduction.

1. Set - C

2. Both Sets - B & C

3. Set - A

4. Set - B

Q. Carbon cannot reduce the oxides of sodium to sodium because

1. $Na$ has less affinity for oxygen
2. $Na$ has more affinity for carbon than oxygen
3. $Na$ is non-reactive
4. $Na$ has more affinity for oxygen than carbon

Q. During electrolysis of molten sodium chloride:

1. sodium is obtained at the cathode and chlorine is obtained at the anode.
2. hydrogen is obtained at the cathode and oxygen is obtained at the anode.
3. sodium is obtained at the anode and chlorine is obtained at the cathode.
4. hydrogen is obtained at the anode and oxygen is obtained at the cathode.

Q.

Complete the following reaction:

$\mathrm{Fe}+\mathrm{S}\stackrel{\mathrm{heat}}{\to }$

Q. Redox reactions play a pivotal role in chemistry and biology. The values of standard redox potential $\left(E_{\ominus }\right)$ of two half cell reactions decided which way the reaction is expected to proceed. A simple example is a Daniell cell in which zinc goes into solution and copper gets deposited. Given below are a set of half cell reactions (acidic medium) along with their $E_{\ominus }$ (V with respect to normal hydrogen electrode) values. Using this data, obtain correct explanations for the following question
$I_2+2e^{-}\to 2I^{\ominus };E^{\ominus }=0.54$
$C{l}_2+2e^{-}\to 2C{l}^{\ominus };E^{\ominus }=1.36$
$M{n}^{3+}+e^{-}\to M{n}^{2+};E^{\ominus }=1.50$
$F{e}^{3+}+e^{-}\to F{e}^{2+};E^{\ominus }=0.77$
$O_2+4H^{⨁}+4e^{-}\to 2H_{2}O;E^{\ominus }=1.23$

While $F{e}^{3+}$ is stable, $M{n}^{3+}$ is not stable in acid solution because

1. $F{e}^{3+}oxidizes{H}_{2}Oto{O}_2$
2. $M{n}^{3+}oxidizes{H}_{2}Oto{O}_2$
3. $O_{2}oxidizesM{n}^{2+}toM{n}^{3+}$
4. $O_{2}oxidizesbothM{n}^{2+}toM{n}^{3+}andF{e}^{2+}toF{e}^{3+}$

Q. The metals sodium, calcium, and magnesium at the top of the reactivity series can be obtained by:

1. reduction of their oxides
2. oxidation
3. electrolysis of their molten chlorides
4. heating

Q. Alkali metals can be used as reducing agents.

1. True
2. False

Q. The metallurgical process in which a metal is obtained in a fused state is called:

1. Roasting
2. Calcination
3. Froth floatation
4. Smelting

Q. Redox reactions play a pivotal role in chemistry and biology. The values of standard redox potential $\left(E_{\ominus }\right)$ of two half cell reactions decided which way the reaction is expected to proceed. A simple example is a Daniell cell in which zinc goes into solution and copper gets deposited. Given below are a set of half cell reactions (acidic medium) along with their $E_{\ominus }$ (V with respect to normal hydrogen electrode) values. Using this data, obtain correct explanations for the following question
$I_2+2e^{-}\to 2I_{\ominus };E^{\ominus }=0.54$
$C{l}_2+2e^{-}\to 2C{I}_{\ominus };E^{\ominus }=1.36$
$M{n}^{3+}+e^{-}\to M{n}^{2+};E^{\ominus }=1.50$
$F{e}^{3+}+e^{-}\to F{e}^{2+};E^{\ominus }=0.77$
$O_2+4H^{⨁}+4e^{-}\to 2H_{2}I;E^{\ominus }=1.23$

While $F{e}^{3+}$ is stable, $M{n}^{3+}$ is not stable in acid solution because

1. $O_{2}oxidizesM{n}^{2+}toM{n}^{3+}$
2. $O_{2}oxidizesbothM{n}^{2+}toM{n}^{3+}andF{e}^{2+}toF{e}^{3+}$
3. $F{e}^{3+}oxidizes{H}_{2}Oto{O}_2$
4. $M{n}^{3+}oxidizes{H}_{2}Oto{O}_2$

Q. How are highly reactive metals reduced?

Q. From the given table, identify the set of metals that cannot be extracted from their ores using carbon reduction method.

1. Set - A
2. Set - B
3. Set - C
4. Both Sets - B & C