Which of the following statement(s) is/are correct in the case of heavy water?

Choose the correct option
1. (a, b)
2. (b, c)
3. (c, d)
4. (a, c)

Which of the following reactions is an example of use of water gas in the synthesis of other compounds?

1.  ${\mathrm{CH}}_4\left(\mathrm{g}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)\underset{\mathrm{Ni}}{\overset{1270 \mathrm{K}}{\to }}\mathrm{CO}\left(\mathrm{g}\right)+{\mathrm{H}}_2\left(\mathrm{g}\right)$

2.  $\mathrm{CO}\left(\mathrm{g}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)\underset{\mathrm{Catalyst}}{\overset{673 \mathrm{K}}{\to }}{\mathrm{CO}}_2\left(\mathrm{g}\right)+{\mathrm{H}}_2\left(\mathrm{g}\right)$

3.  ${\mathrm{C}}_{\mathrm{n}}{\mathrm{H}}_{2\mathrm{n}+2}+{\mathrm{nH}}_2\mathrm{O}\left(\mathrm{g}\right)\underset{\mathrm{Ni}}{\overset{1270 \mathrm{K}}{\to }}\mathrm{nCO}+(2\mathrm{n}+1){\mathrm{H}}_2$

4.  $\mathrm{CO}\left(\mathrm{g}\right)+2{\mathrm{H}}_2\left(\mathrm{g}\right)\underset{\mathrm{Catalyst}}{\overset{\mathrm{Cobalt}}{\to }}{\mathrm{CH}}_3\mathrm{OH}\left(\mathrm{l}\right)$

Some of the properties of water are described below. Which of them is/are not correct?

1. (a, b)
2. (b, c)
3. (c, d)
4. (a, d)