In a closed container, a liquid is stirred with a paddle to increase the temperature. Which of the following is true ?

• $∆\mathrm{E} = \mathrm{W} \ne 0, \mathrm{q}= 0$

• $∆\mathrm{E} = \mathrm{W} =\mathrm{q} \ne 0$

• $∆\mathrm{E} =0, \mathrm{W} = \mathrm{q}\ne 0$

• $\mathrm{W} =0, ∆\mathrm{E}= \mathrm{q}\ne 0$

If an allotropic form changes slowly to a stable form. It is called

• enantiotropy

• dynamic allotropy

• monotropy

• None of the above

The amount of energy released when 20 mL of 0.5 M NaOH are mixed with 100 mL of 0.1 M HCl is x kJ. The heat of neutralisation is (in kJ mol^-1).

• -100x

• -50x

• +100x

• +50x

The number of antibonding electron pairs in ${\mathrm{O}}_2^{2-}$ molecular ion on the basis of molecular orbital theory is

• 2

• 3

• 4

• 5

Two organic compounds (A) and (B) both containing only carbon and hydrogen, on quantitative analysis gave the same percentage composition by weight

$\mathrm{C}=\left(\frac{12}{13}\right) \times 100 \% \mathrm{H}= \left(\frac{1}{13}\right) \times 100\%$

A decolourises bromine water but B does not. A and B respectively are

• C₂H₂ and C₆H₆

• C₆H₆ and C₂H₂

• C₂H₄ and C₂H₆

• C₂H₂ and C₂H₆

The standard molar heat of formation of ethane, CO₂ and water (l) are -21.1, -94.1 and -68.3 kcal respectively. The standard molar heat of combustion of ethane will be

• -372 kcal

• 162 kcal

• -240 kcal

• 183.5 kcal

Which of the following is isostructural with CO₂ ?

• N₂O

• NO₂

• N₂O₅

• NO

The pH of a buffer solution containing equal molal concentration of a weak base and its chloride (K_b for weak base = 2 x 10^-5) is 

• 5

• 9

• 4.7

• 9.3

9.

Consider the following equilibrium in a closed container

        ${\mathrm{N}}_2{\mathrm{O}}_4\left(\mathrm{g}\right) \rightleftharpoons 2{\mathrm{NO}}_2\left(\mathrm{g}\right)$

At a fixed temperature, the volume of the reaction container is halved. For this change which of the following statement holds true regarding the equilibrium constant (K_p) and degree of dissociation ($\mathrm{\alpha }$)?

• Neither K_P nor $\mathrm{\alpha }$ changes

• Both K_p and $\mathrm{\alpha }$ changes

• K_p changes but $\mathrm{\alpha }$ does not

• K_p does not change but $\mathrm{\alpha }$ changes

How many grams of dibasic acid (mol. wt. 200) should be present in 100 mL of the aqueous solution to give 0.1 N?

• 10 g

• 20 g

• 2 g

• 1 g