Dimethyl glyoxime gives a red precipitate with Ni²⁺, which is used for its detection. To get this precipitate readily the best pH range is

• < 1

• 2-3

• 3- 4

• 9- 11

The statement true for ${\mathrm{N}}_3^{-}$ is

• it has a non-linear structure

• it is called pseudohalogen

• the formal oxidation state of nitrogen in this anion is -1

• it is isoelectronic with NO₂

Shape of O₂F₂ is similar to that of

• C₂F₂

• H₂O₂

• H₂F₂

• C₂H₂

4.

The liquefied metal expanding on solidification is

• Ga

• Al

• Zn

• Cu.

The compound insoluble in water is

• mercurous nitrate

• mercuric nitrate

• mercurous chloride

• mercurous perchlorate.

The ONO angle is maximum in

• ${\mathrm{NO}}_3^{-}$

• ${\mathrm{NO}}_2^{-}$

• ${\mathrm{NO}}_2$

• ${\mathrm{NO}}_2^{+}$

The dipole moment is the highest for

• trans-2-butene

• 1,3-dimethylbenzene

• acetophenone

• ethanol.

For principle quantum number n = 4, the total number of orbitals having l= 3 is

• 3

• 7

• 5

• 9

How much energy is released when 6 moles of octane is burnt in air? Given $∆{\mathrm{H}}_{\mathrm{f}}^{°}$ for CO_2(g) , H₂O_(g) and C₈H_18(l)  respectively are - 490, -240 and +160 kJ/mol.

• -6.2 kJ

• -37.4 kJ

• -35.5 kJ

• -20.0 kJ

For the equilibrium ${\mathrm{H}}_2{\mathrm{O}}_{\left(\mathrm{l}\right)} \rightleftharpoons {\mathrm{H}}_2{\mathrm{O}}_{\left(\mathrm{g}\right)}$ at 1 atm and 298K.

• standard free energy change is equal to zero ($∆{\mathrm{G}}^{°}$= 0)

• free energy change is less than zero ($∆{\mathrm{G}}^{°}$ < 0)

• standard free energy change is less than zero ($∆{\mathrm{G}}^{°}$< 0)

• standard free energy change is greater than zero ($∆$G° > 0).