Pumice is the name of the most common volcanic rock that floats. It has various air bubbles and capillaries which trap air. Which statement is correct for this rock

• Air cavities are interconnected

• Air cavities are not connected

• Density of rock is more than water

• Rock is very older

2.

The correct configuration for given structure is :

• L-configuration

• D-configuration

• R-configuration

• S-configuration

High Biological Oxygen demand in water body indicates

• Chemical pollution

• Organic pollutant

• High photoautotroph

• Pressure of heterotrophs

What amount has to be taken from 11 N HCl to make 50 mL of 2N HCl :

• 11.0 mL

• 9.09 mL

• 6.03 mL

• 2.0 mL

Slope of line in given plot will be

• -1

• -1/2

• +1/2

• 2

If a reactangle is inscribed in circle of diameter 'D'. Then the area of rectangle will be: 

• Independent of length and breadth

• Will be always smaller than D²/2

• Will be always smaller than D²/4

• Will be always greater than D²/4

Which of the following element is required for production of thyroxin?

• NaCl

• Iodine

• Bromine

• Fluorine

Temperature above which gas cannot be liquified even by applying pressure is termed as-

• Critical temperature

• Boyle temperature

• Curie temperature

• Charles temperature

If a nail is hammered in the bark of tree at height 4 m, after ten years the height of tree is doubled. Then the height of nail will be:

• 4 m

• 8 m

• 16 m

• 10 m

Lassaigne's test is employed to detect the presence of nitrogen, sulphur, halogens and phosphorus in an organic compound. These elements are present in the covalent form in an organic compound. On treatment with sodium metal covalent carbon of organic compound are converted into which ionic forms:

• Cyanide

• Suphide

• Nitrate

• Carbide