The disease caused by deficiency of vitamin B₁ is:

1.	Convulsions	2.	Beri-beri
3.	Cheilosis	4.	Sterility

Among the following compounds the one that is most reactive towards electrophilic nitration is:
1. Benzoic acid
2. Nitrobenzene
3. Toluene
4. Benzene

Buffer solutions have constant acidity and alkalinity because:
 

The correct order of decreasing acid strength of
trichloroacetic acid (A), trifluoroacetic acid (B), acetic acid (C), and formic acid (D) is:

1. B > A > D > C

2. B > D > C > A

3. A > B > C > D

4. A > C > B >D

Sucrose can be formed by:
1. α–D–galactopyranose and α–D–glucopyranose
2. α–D–glucopyranose and β–D–fructofuranose
3. β–D–galactopyranose and α–D–fructofuranose
4. α–D–galactopyranose and β–D–fructopyranose

The enthalpy of fusion of water is 1.435 kcal/mol. The molar entropy change for the melting of ice at 0 ^oC is:

Isostructural pair among the following is:

1. ${\mathrm{BCl}}_3$ $\mathrm{and}$ ${\mathrm{BrCl}}_3$

2. ${\mathrm{NH}}_3$ $\mathrm{and}$ ${\mathrm{NO}}_3^{-}$

3. ${\mathrm{NF}}_3$ $\mathrm{and}$ ${\mathrm{BF}}_3$

4. ${\mathrm{BF}}_4^{-}$ $\mathrm{and}$ ${\mathrm{NH}}_4^{+}$

The bond order of 1.5 is shown by:  

Which one of the following is not a condensation polymer?

1. Melamine

2. Glyptal

3. Dacron

4. Neoprene

The end product (C) in the below-mentioned reaction is:
\(H_3C-Br\xrightarrow{\bf KCN }A\xrightarrow{ \bf H_3O^+~~}B\xrightarrow[\bf\text{Ether}]{~~LiAlH_4~~}C\)