Page 180 - Chemistry ICSE Class X

166 ICSE Chemistry – 10
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8. How can you predict the preferential discharge of OH , I , Br , Cl , NO , and SO , during electrolysis on the
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basis of electrochemical series for anions.
9. (a) Name three industrial chemicals which are manufactured by electrolytic method.
(b) Mention three objectives of electroplating.
10. Draw a labelled diagram to show electroplating of nickel on an aluminium spoon.
11. Name the electrolyte which is used in the electroplating of silver.
12. (a) What is electrometallurgy?
(b) Name three metals which are obtained by electrolytic method.

(c) At which electrode these metals would appear?
13. Give reason for the following:
(a) Electrolysis of molten lead bromide is considered to be a reaction in which oxidation and reduction go side
by side, i.e., a redox reaction.
(b) The blue colour of aqueous copper sulphate fades when it is electrolysed using platinum electrodes.
(c) The ratio of hydrogen and oxygen formed at the cathode and anode is 2 : 1 by volume.

F +P VJG GNGEVTQN[UKU QH CEKFKſGF YCVGT FKNWVG UWNRJWTKE CEKF KU RTGHGTTGF VQ FKNWVG PKVTKE CEKF HQT CEKFKſECVKQP
(e) A graphite (or carbon) anode is preferred to other inert electrodes during electrolysis of fused lead bromide.
14. %JQQUKPI QPN[ YQTFU HTQO VJG HQNNQYKPI NKUV YTKVG FQYP VJG CRRTQRTKCVG YQTFU VQ ſNN KP VJG DNCPMU (a) to (e)
below:
anions, anode, cathode, cations, electrode, electrolyte, nickel, voltameter
To electroplate an article with nickel requires an (a) ___________ which must be a solution containing
(b) ___________ ions. The article to be plated is placed as the (c) ___________ of the cell in which the plating
is carried out. The (d) ___________ of the cell is made from pure nickel. The ions that are attracted to the
negative electrode and discharged these are called (e) ___________ .
15. (a) What are the objectives of electroplating?

(b) Write down the various steps involved in electroplating.
16. State the electrode reaction at the anode during the electrolysis of
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(b) aqueous nickel sulphate solution using nickel anode.

(c) pure alumina (Al O ).
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(d) fused lead bromide.
17. Fill in the blanks.
(a) During electrolysis, positive ions move towards ___________ .

(b) Molten lead bromide conducts electricity. It is called an ___________ . It is composed of lead ___________
and bromine ___________ . The lead ions are ___________ charged and are called ___________. The bromine
___________ are ___________ charged and are called ___________ .
(c) NaCl is a poor conductor of electricity in the ___________ .
(d) A solution of FeSO _________ kept in zinc vessel.
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(e) The electron-releasing tendency of zinc is ___________ than that of copper.
(f) Zinc is ___________ in the activity series than iron.
(g) A solution of HCl gas in water conducts electricity because ___________, but a solution of HCl gas in toluene
does not conduct an electricity because ___________ .