Thursday, August 23, 2012

MCQ Sample Question Paper X Based On Practical skill CBSE Board

MCQ
Sample Question Paper  X  Based On Practical skill
1.
When we start heating a mixture of sulphur powder and iron fillings, we would observe  that

(a) Surphur starts melting.                   (b) Iron filings start melting.

(c) Mixture becomes red hot.  (d) mixture evaporates
Ans
(a) Sulphur has a lower melting point than iron.
2
A student added 2 drops of iodine solution into 4 ml of starch solution in test tube  A, another student added 2 ml of starch solution into 4 ml of iodine solution in test tube B. They would then observe

(a) a change of colour to blue black in test tube A but not in test tube B.

(b) a change of colour to blue black in test tube B but not in test tube A.

(c) a change of colour to blue black in both test tubes A and B

(d) no change of colour in any test tube.
Ans
(c) Iodine + starch solution Blue - black colour.
3
A student observed that the colour of pH paper changed to green when she dipped it in water. She added a few drops of concentrated hydrochloric acid to the water. The colour of pH would turn to

(a) light red.                                        (b) apple green.

(c) dark blue.                                       (d) lemon yellow.
Ans
(a) The colour of pH paper is green in neutral medium, whereas it is red
in acidic medium.
4
10 mL of freshly prepared iron sulphate was taken in each of four test tubes. Strips of copper, iron, zinc and aluminium were introduced, each metal in a different test tube. A black residue was obtained in two of them. The right pair of metals forming the precipitates is

(a) copper and zinc.                     (b) aluminium and copper.

(c) iron and aluminium.                   (d) zinc and aluminium.
Ans
(d) Zinc and aluminium being more reactive will replace iron from iron sulpate.
5
The colour of NO2 and PbO formed when lead nitrate is heated are :

(a) brown and green                        (b) brown and yellow

(c) brown and colourless                (d) colourless and yellow
Ans
(b) NO2 is brown and PbO is yellow.
6
When you place iron nail in copper sulphate solution, the reddish brown coating formed on the nail is


(a) soft and dull.                    (b) hard and flaky.

(c) smooth and shining.        (d) rough and granular
Ans
(a) The freshly deposited copper is soft and dull.
7
Which of the following is a correct observation when water is added to lime?

(a) No change and a hissing sound

(b) Vigorous bubbling and a hissing sound

(c) Slow bubbling with no sound

(d) Vigorous bubbling with evolution of heat and a hissing sound
Ans
(a) The reactions between (i) Zinc and dil. HCl and (ii) dil HCl and Na2CO3 are fast whereas the reaction between Zn and NaOH is slow. There is no reaction between NaOH and Na2CO3
8
On heating ferrous sulphate crystals, one would get

(a) Sweet smell                                  (b) lotten egg smell

(c) irritating, choking smell              (d) none of the above
Ans:
(c) It is decomposition reaction is which SO2 and SO3 are liberated which are pungent smelling gases.

What happens when dilute hydrochloric acid is added to iron fillings?

(a) Chlorine gas and iron hydroxide are produced

(b) No reaction takes place

(c) Iron salt and water are produced

(d) Hydrogen gas and iron chloride are produced
Ans
Hydrogen gas and iron chloride are produced

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