31.

The role of copper diaphragm in Whytlaw-Gray's method is

• preventing the corrosion of electrolytic cell

• preventing the mixing of H₂ and F₂

• as anode

• as cathode

Liquid X is used in bubble chamber to detect neutral mesons and gamma photons. Then, X is

• He

• Ne

• Kr

• Xe

Which of the following is not added durig the extraction of silver by cyanide process?

• NaCN

• Air

• Zn

• Na₂S₂O₃

Which one of the following gives Prussian blue colour?

• Fe₂[Fe(CN)₆]

• Na₄[Fe(CN)₆]

• Fe₃[Fe(CN)₆]₃

• Fe₄[Fe(CN)₆]₃

The products formed, in the reaction of phenol with Br₂ dissolved in CS₂ at 0°C are

• o-bromo, m-bromo and p-bromophenols

• o-bromo and p-bromophenols

• 2,4,6-tribromo and 2,3,6-tribromophenols

• 2,4-dibromo and 2,6-dibromophenols

The structure of PCC is

• C₆H₅HCrO₂

• C₆H_{5$\stackrel{\oplus }{\mathrm{N}}$}HCrO₂${\mathrm{Cl}}^{⊝}$

• C₅H₅$\stackrel{\oplus }{\mathrm{N}}$HCrO₂${\mathrm{Cl}}^{⊝}$

• C₅H₅$\stackrel{\oplus }{\mathrm{N}}$HCrO₃${\mathrm{Cl}}^{⊝}$

Identify X and Y in the following reactions-

Example of a biodegradable polymer pair is

• nylon-6, 6 and terylene

• PHBV and dextron

• bakelite and PVC

• PET and polyethylene

The number of hydrogen bonds between guanine and cytosine and between adenine and thymine in DNA is

• 1, 2

• 3, 2

• 3, 1

• 2, 1

Identify phenacetin from the following-