131.

To weld metals together, high temperature is required. Such a high temperature is obtained by burning:

• Acetylene in oxygen

• LPG in oxygen

• Methane in oxygen

• Acetylene in nitrogen

Match List-I with List-II

List I (Element)

1. Li
2. Na
3. K
4. Cs

List II (Use)

1. Time keeper in atomic clocks
2. Batteries
3. Transfer of nerve impulses
4. Control of thewater content in the blood

• (a) - 2, (b) - 3, (c) - 4, (d) - 1

• (a) - 1, (b) - 2, (c) - 3, (d) - 4

• (a) - 2, (b) - 4, (c) - 3, (d) - 1

• (a) - 1, (b) - 3, (c) - 2, (d) - 4

The symbol of the element 'Tungsten' is:

• Ta

• W

• Tl

• Tc

Which one of the following statements is correct?

• Rutherford's alpha-particle scattering experiment led to the discovery of electron

• J J Thomson suggested that the nucleus of an atom contains protons

• The atomic number of an element is the same as the number of protons in the nucleus of its atom

• The mass number of an atom is equal to the number of electrons in its shells

The alkali metals have relatively low melting point. Which one of the following alkali metals is expected to have the highest melting point?

• Li

• Na

• K

• Rb

The number of valence electrons in the O^2- ion is

• 4

• 6

• 8

• 10

Which one of the following is the correct electronic configuration of chlorine?

• 2, 7, 8

• 2, 8, 7

• 2, 8, 8

• 7, 8, 2

In honey, which one among the following sugars predominates?

• Sucrose

• Fructose

• Galactose

• Maltose

The number of aluminium ions present in 54 g of aluminium (atomic weight 27) is

• 2

• 18

• 1.1 X 10²⁴

• 1.2 x 10²⁴

The most stable form of carbon is

• diamond

• graphite

• fullerene

• coal