Question

10. State the type of chemical reaction used for extraction of iron from their
naturally occuring oxides.
11. Account for the following:
(1) White silver chloride turns grey in sunlight.
(ii) Brown coloured copper powder on heating in air turns into black
coloured substance.
12. A metal X burn with a dazzling white light leaves a white powder 'Y' which
dissolves in water and turns red litrus blue. Identify X and Y. Give chemical
cquations involved.
13. Why are some medicines and chemicals are stored in amber coloured
bottles?
14.Iron nails are take in three test tubes - A having water, B having boiled
water and a layer of oil and C having anhydrous CaCl2. In which test tube
the nails will undergo corrosion? Give reason.
15. Identify and name the compound:
(a) There is a smell of chlorine from the open container
(b) White cast present on the fractured arm of a person
(c) A powder added by milk man to the milk to turn it slightly alkaline.
16. What are the products formed by the electrolysis of NaCl solution.?
17. How are bases different from alkalis? Are all bases alkali?
18. When zinc metal is treated with a dilute solution of strong acid, a gas is
evolved, which is utilised in the hydrogenationof oil. Name the gas evolved.
Write the chemical equation for the reaction involved and also write a test to
detect the gas formed.
19. Differentiate between strong and weak acids. Identify strong and weak acid
from the following: Hydrochloric acid, acetic acid, formic acid, nitric acid and
phosphoric acid.
20. Water is a neutral solution. What colour will you get when you add a few
drops of universal indicator in a test tube containing distilled water?
a. Il compound X turns pH paper orange and compound Y turns it red, which
compound is a strong acid?
22. Why does a flow of acid rain water into a river make the survival of aquatic
life in the river difficult?
23. Give reasons for the following:
(a) We feel burning sensation in the stomach when we over eat.
(b) The crystals of washing soda change to white powder on exposure to ai
(C) The tarnished copper vessels shine when rubbed with lemon.
(d) The aqueous solution NaCl is neutral but an aqueous solution sodium
carbonate is base.
24. How would you distinguish between baking powder and washing soda by
heating.?
25. What is the difference between plaster of paris and gypsum and how it can be
inter converted?​

Answer 1

Answer:

10.Reduction using carbon.

11.(1).Photolytic reaction.

(2). Combustion Reaction

12.x=magnesium

y- magnesium oxide.

2Mg + O2 gives 2MgO.