Question

True or False : Non-metallic oxides are acidic in nature. True or False : When pH of inside mouth decreases than 6.5 it gets corroded.

Which metal is kept immersed in kerosene to make it protected and prevent fire ?

(A) Potassium (B) Sodium (Na) (C) (A) & (B) both (D) Magnesium (Mg)

What is meant by extraordinary capacity of carbon of forming bond with other carbon

atoms ? Choose the proper option.

(A) Catenation (B) Tetrad valency (C) Saturated (D) Covalency True or False : The valency of group-17 elements is 7.
converts complex components of food into simple components.

(A) Minerals (B) Enzymes (C) Carbon dioxide (D) Nitrogen In photosynthesis carbon dioxide is reduced into Which are the main parts of the brain ? True or False : In environment, some sudden action in response to something is called reflex action. Give explanation of two types of pollination. True or False : 14

plants are seen short in F

2

generation. True or False : Concave lens are used as shaving mirrors. If the size of the scattering particles is large, the scattered light appear

The component of white light with greatest wavelength is

(A) violet (B) Red (C) Green (D) Blue SI unit of electric charge is .

A wire of resistance 10

W is connected to a battery, the electric current flow in the wire is 1.5 V

.

True or False : Infrared rays are responsible for the greenhouse effect. What is the best energy source ? Who started the ‘Chipko Movement’ ?

What is the chemical formula of marble ?

(A) Na

2CO

3

(B) CaCO

3

(C) BaCO

3

(D) Ca(OH)

2

What is meant by bad ozone ? The focal length of a concave lens of power + 5.0 D will be cm.

Why are decomposition reactions called the opposite of combination reactions ? Write equations

for these reactions.

Explain with reason : Why the hydrogen gas is not produced by reaction of metals with Nitric

acid ?

Samples of four metals A, B, C and D were taken and added to the following solution one by

one. The results obtained have been tabulated as follows.

Use the Table above to answer the following questions about metals A, B, C and D.

(i) Which is the most reactive metal ?

(ii) What would you observe if B is added to a solution of Copper (II) sulphate ?

(iii) Arrange the metals A, B, C and D in the order of decreasing reactivity.

Metal Iron (II) sulphate Copper (II) sulphate Zinc sulphate Silver nitrate

A No reaction Displacement – –

B Displacement – No reaction
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Answer 1

Answer:

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