CBSE Chemistry Model Test Paper : Set V
1. What is the chemical name of baking soda? Write its formula.
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2. The pH values of equimolar solutions of three acids A, B and C are 2.5, 6.5 and 4.2 respectively. Arrange the acids in order of increasing hydrogen ions concentration.
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3. A statue made of bronze was kept in a museum. After some time it was found that the statue had lost its lustre due to the formation of a greenish layer on its surface. Name the phenomenon responsible for this happening. What is the name of the greenish substance?
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4. When acidified hydrogen peroxide is added to a solution of KI, iodine is liberated according to the following equation:
H2 O2 + 2 KI + H2 SO4 ——–> 2H2 O + I2 + K2 SO4
It was found that the concentration of iodine increases from 0 to 8.60 x 10-6 mol L-1 in 20 seconds. Calculate the rate of reaction during this time interval.
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5. What do you mean by quenching and annealing of steel?
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6. (a) Write the reactions that take place during the manufacture of sulphuric acid by contact process.
(b) What would you observe when cone. H2 SO4 is added to sugar? Explain your observation.
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7. What are polyesters and polyamides? Write an equation for the formation of these polymers.
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8. (a) What is denatured alcohol?
(b) Write chemical equations of the reaction of propanone with (i) sodium borohydride. (ii) alkaline potassium permanganate.
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9. Write an equation for the reaction of
(a) iron with steam.
(b) calcium with water.
© sodium with hydrogen.
Or
(a) A polymer has the following structure.
—CH2 —— CH ——- CH2 ——– CH —– CH2 — – CH——
I I I
CH3 CH3 CH3
(i) Write the name of the monomer of the above polymer. (ii) Is it an addition polymer or a condensation polymer?
(b) Which type of reaction occurs when soap is formed from fats.
(b) Why do the branched chain detergents cause pollution of rivers and water bodies?
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10. Name the chief ore of aluminium. With the help of a labelled diagram and necessary chemical equations, explain how aluminium is extracted from its ore. What is the function of adding cryolite in this process?
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