Page 160 - Science Class 08

2. The electrode connected to the posi ve terminal of ba ery is:
(a) cathode (b) anode

(c) ca on (d) ion
3. We cannot use electrolysis for:
(a) refining gold (b) obtaining aluminium

(c) obtaining hydrogen gas (d) none of these
4. Electropla ng cannot be used for:
(a) making decora ve items (b) making jewellery
(c) protec ng iron from rus ng (d) none of these

B. Fill in the blanks.
1. Most liquids that conduct electricity are solu ons of _______________ , bases and
________________.
2. The nega ve terminal of a ba ery is also called _______________ .
3. During electrolysis, ions with a posi ve electrical charge move towards the
_______________.
4. In electropla ng, the object to be electroplated is made the _______________ by
connec ng it to the nega ve.
5. On passing electric current through the solu on of CuSO₄, copper ions move towards the
_______________charged cathode.

C. Write True or False.
1. Water can conduct electricity if salt is present in it.
2. Decomposi on takes place when electricity is passed through electrolytes.
3. Nega vely charged ions are called ca ons.

4. Electrolysis can be used to produce caus c soda.
5. Electrolyte is an ionic compound of metal which has to be deposited.
D. Very short answer questions.
1. What is electric current?

2. When does the decomposi on takes place?
3. What do you mean by ions?
4. Why is electrolysis used?
5. What are insulators?

6. What is ac ve electrodes?
7. What is electroly c cell?
E. Short answer ques ons.

1. What are electrodes?
2. What is cathode?
3. What happens when electricity is passed through water?
4. What do you mean by electrolytes?

160 Science-8