Arrange the following in the order of increasing mass (atomic mass O = 16, Cu = 63, N = 14)

I. One atom of oxygen

II. One atom of nitrogen

III. 1 × 10^-10 mole of oxygen

IV. 1 × 10^-10  mole of copper

• II < I < III < IV

• I < II < III < IV

• III < II < IV < I

• II < IV < I < III

Which transition in the hydrogen atomic spectrum will have the same wavelength as the transition will have the same wavelength, n = 4 to n = 2 of He⁺ spectrum?

• n = 4 to n = 3

• n = 2 to n = 1

• n = 4 to n = 2

• n = 3 to n = 1

Which of the following is not correct with respect to bond length of the species? 

• C₂ > ${\mathrm{C}}_2^{2-}$

• ${\mathrm{B}}_2^{+}$ > B₂

• ${\mathrm{Li}}_2^{+}$ > Li₂

• O₂ > O${}_2^{-}$

Intramolecular hydrogen bond is present in

• water

• o-nitrophenol

• p-nitrophenol

• methylamine

A mixture of ethane and ethene occupies 41 L at 1 atm and 500 K. The mixture reacts completely with $\frac{10}{3}$mole of O₂ to produce CO₂ and H₂O. The mole fraction of ethane and ethene in the mixture are respectively (R = 0.082 L atm K^-1 mol^-1)

• 0.50, 0.50

• 0.75, 0.25

• 0.67, 0.33

• 0.25, 0.75

Substance which is weakly repelled by a magnetic field is

• O₂

• H₂O

• CrO₂

• Fe₃O₄

The correct decreasing order of first ionisation enthalpies of five elements of the second period is

• Be > B > C > N > F

• N > F > C > B > Be

• F > N > C > Be > B

• N > F > B > C > Be

In the reaction H₂S+ H₂O₂ → S+ 2H₂O

• H₂S is an acid and H₂O₂ is a base

• H₂S is a base and H₂O₂ is an acid

• H₂S is an oxidising agent and H₂O₂ is a reducing agent

• H₂S is an reducing agent and H₂O₂ is a oxidising agent

The bonds present in the structure of dichromate ion are

• four equivalent Cr-O bonds only

• six equivalent Cr-O bonds and one Cr - O - O bond

• six equivalent Cr-O bonds and one O-O bond

• eight equivalent Cr-O bonds

Molar heat capacity of aluminium is 25 JK^-1 mol^-1. The heat necessary to raise the temperature of 54 g of aluminium (atomic mass 27 g mol^-1) from 30°C to 50°C is

• 1.5 kJ

• 0.5 kJ

• 1.0 kJ

• 2.5 kJ