31.

In face centred cubic unit cell edge length is :

• $\frac{4}{\sqrt{3}}$r

• $\frac{4}{\sqrt{2}}$r

• 2r

• $\frac{\sqrt{3}}{2}$r

If the Zn²⁺/Zn electrode is diluted to 100 times then the change in emf :

• increase of 59 mV

• decrease of 59 mV

• increase of 29.5 mV

• decrease of 29.5 mV

Which of the following reactions end infinite time ?

• Zero order

• 1st order

• 2nd order

• 3rd order

If equivalent conductance of 1 M benzoic acid is 12.8 ohm^-1 cm and if the conductance of benzoate ion and H⁺ ion are 42 and 288 .42 ohm^-1 cm² respectively .Its degree of dissociation is :

• 39 %

• 3.9 %

• 0.35 %

• 0.039 %

If two substances A and B have ${\mathrm{P}}_{\mathrm{A}}^{°}$ : ${\mathrm{P}}_{\mathrm{B}}^{°}$ = 1 : 2 and have mole fraction in solution 1 : 2 then mole fraction of A in vapours :

• 0.33

• 0.25

• 0.52

• 0.2

If an aqueous solution of glucose is allowed to freeze then crystal of which will be separated out first ?

• Glucose

• Water

• Both (a) and (b)

• None of these

A + 2B $\to$ C + D , if

- $\frac{\mathrm{d}\left[\mathrm{A}\right]}{\mathrm{dt}}$ = 5 x 10^-4 mol L^-1 s^-1 , then - $\frac{\mathrm{d}\left[\mathrm{B}\right]}{\mathrm{dt}}$ is

• 2.5 x 10^-4 mol L^-1 s^-1

• 50 x 10^-4 mol L^-1 s^-1

• 2.5 x 10^-3 mol L ^-1 s^-1

• 1.0 x 10^-3 mol L ^-1 s^-1

Which statement is wrong for NO ?

• It is anhydride of nitrous acid

• Its dipole moment is 0.22 D

• It forms dimer

• It is paramagnetic

There is no S-S bond in :

• S₂O₄^2-

• S₂O₅^2-

• S₂O₃^2-

• S₂O₇^2-

CuSO₄ does not react with :

• Fe

• Ag

• Zn

• Mg