Page 2 - 4. HOME ASSIGNMENT-COMBINATION & DECOMPOSITION REACTION)

Subjective questions-

Q1. Photographic fixer is a mixer of chemicals used in the final step in the
photographic processing of film or paper. The fixer stabilises the image, removing
the unexposed silver halide remaining on the photographic film or photographic
paper, leaving behind the reduced metallic silver that forms the image.
i) Name the Silver halide & write its formula.
ii) Is there a chemical reaction undergone? If yes, then write its type.
iii) How will you confirm that a chemical change has taken place.
Pen down the chemical equation associated with the change.
.
Q2. 2 g of ferrous sulphate crystals were heated in a hard glass test tube and
observations recorded.
a. What type of odour is observed on heating ferrous sulphate crystals?
b. Name the products obtained on heating ferrous sulphate crystals.
c. What type of reaction is taking place.

Q.3 A substance X, which is an oxide of a group 2 element, is used intensively in the
cement industry. This element is present in bones also. On treatment with water it
forms a solution which turns red litmus blue. Identify X and also write the chemical
reactions involved.

Q.4 Why do we store silver chloride in dark coloured bottles?

Q.5 On heating blue coloured powder of copper (II) nitrate in a boiling tube, copper
oxide (black), oxygen gas and a brown gas X is formed.
(a) Write a balanced chemical equation of the reaction.
(b) Identify the brown gas X evolved.
(c) Identify the type of reaction.
(d) What could be the pH range of aqueous solution of the gas X?
White silver chloride in sunlight turns to-
(a) grey (b) yellow
(c) remain white (d) red

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