Argon is used

• in filling airships

• to obtain low temperature

• in high temperature welding

• in radiotherapy for treatment of cancer

The number of electrons, neutrons and protons in a species are equal to 10, 8 and 8 respectively. The proper symbol of the species is

• ${}_8{}^{16}\mathrm{O}$

• ${}_8{}^{18}\mathrm{O}$

• ${}_{10}{}^{18}\mathrm{Ne}$

• ${}_8{}^{16}\mathrm{O}^{2-}$

56 g of nitrogen and 96 g of oxygen are mixed isothermally and at a total pressure of 10 atrn. The partial pressures of oxygen and nitrogen (in atm) are respectively

• 4, 6

• 5, 5

• 2, 8

• 6, 4

The metal that produces red-violet colour in the non-luminous flame is

• Ba

• Ag

• Rb

• Pb

According to the first law of thermodynamics which of the following quantities represents the change in a state function?

• q_rev

• q_rev - W_rev

• $\frac{{\mathrm{q}}_{\mathrm{rev}}}{{\mathrm{W}}_{\mathrm{rev}}}$

• q_rev + W_rev

The expression for the solubility product of Ag₂CO₃ will be

• K_sp = s²

• K_sp = 4s³

• K_sp = 27s⁴

• K_sp = s

A 600 W mercury lamp emits monochromatic radiation of wavelength 331.3 nm. How many photons are emitted from the lamp per second? (h = 6.626x 10^-34 J-s; velocity of light = 3x10⁸ ms^-1)

• 1 x 10¹⁹

• 1 x 10²⁰

• 1 x 10²¹

• 1 x 10²³

Which of the following fluorides does not exist?

• NF₅

• PF₅

• AsF₅

• SbF₅

Red lead is

• PbO

• PbO₂

• Pb₃O₄

• Pb₂O₃

20.

Which will liberate bromine from a solution of potassium bromide?

• I₂

• Cl₂

• SO₂

• HI