The correct order of decreasing length of the bond as indicated by the arrow in the following structures is

• I >II > III

• II > I > III

• III > II > I

• I > III > II

12.

An atomic nucleus having low n/p ratio tries to find stability by

• the emission of an $\mathrm{\alpha }$-particle

• the emission of a positron

• capturing an orbital electron (K-electron capture)

• emission of a $\mathrm{\beta }$-particle

$( {}_{32}\mathrm{G}^{76}, {}_{34}\mathrm{Se}^{76}) \mathrm{and} ( {}_{14}\mathrm{Si}^{30}, {}_{16}\mathrm{S}^{32})$are example of 

• isotopes and isobars

• isobars and isotones

• isotones and isotopes

• isobars and isotopes

₉₈Cf²⁴⁶  was formed along with a neutron when an unknown radioactive substance was bombarded with ₆C¹². The unknown substance was 

• ₉₁Pa²³⁴

• ₉₀Th²³⁴

• ₉₂U²³⁵

• ₉₂U²³⁸

The values of $∆$H and $∆$S of a certain reaction are -400 kJ mol^-1 and -20 kJ mol^-1K^-1 respectively. The temperature below which the reaction is spontaneous, is

• 100 K

• 20$°$C

• 20 K

• 120$°$C

The correct statement regarding the following energy diagrams is

• Reaction M is faster and less exothermic than reaction N

• Reaction M is slower and less exothermic than reaction N

• Reaction M is faster and more exothermic than reaction N

• Reaction M is slower and more exothermic than reaction N

Commercial sample of H₂O₂ is labeled as 10 V. Its % strength is nearly

• 3

• 6

• 9

• 12

The enthalpy of vaporisation of a certain liquid at its boiling point of 35°C is 24.64 kJ mol^-1. The value of change in entropy for the process is

• 704 JK ^-1mol^-1

• 80 JK ^-1mol^-1

• 24.64 JK ^-1mol^-1

• 7.04 JK^-1mol^-1

Given that

$$\begin{gathered} \mathrm{C} + {\mathrm{O}}_2 \to {\mathrm{CO}}_2; ∆\mathrm{H}°= -\mathrm{x} \mathrm{kJ} \\ 2\mathrm{CO} + {\mathrm{O}}_2 \to 2{\mathrm{CO}}_2; ∆\mathrm{H}°= -\mathrm{y} \mathrm{kJ} \end{gathered}$$

The heat of formation of carbon monoxide will be

• $\frac{y- 2x}{2}$

• y + 2x

• 2x - y 

• $\frac{2\mathrm{x}-\mathrm{y}}{2}$

In case of heteronuclear diatomics of the type AB, where A is more electronegative than B, bonding molecular orbital resembles the character of A more than that of B. The statement

• is false

• is true

• cannot be evaluated since data is not sufficient

• is true only for certain systems