The processes among the following that occur spontaneously are :

1. (a, b)

2. (b, c)

3. (c, d)

4. (a, d)

For the reaction, 2Cl(g) $\to$ Cl₂(g), the correct option is:

1. ${∆}_{\mathrm{r}}\mathrm{H}>0 \mathrm{and} {∆}_{\mathrm{r}}\mathrm{S}<0$

2. ${∆}_{\mathrm{r}}\mathrm{H}<0 \mathrm{and} {∆}_{\mathrm{r}}\mathrm{S}>0$

3. ${∆}_{\mathrm{r}}\mathrm{H}<0 \mathrm{and} {∆}_{\mathrm{r}}\mathrm{S}<0$

4. ${∆}_{\mathrm{r}}\mathrm{H}>0 \mathrm{and} {∆}_{\mathrm{r}}\mathrm{S}>0$

If for a certain reaction ${∆}_{r}H$ is 30 kJ mol^–1 at 450 K, the value of ${∆}_{r}S$ (in JK^–1 mol^–1) for which the same reaction will be spontaneous at the same temperature is:

The entropy change for the melting of 'x' moles of ice at 273 K and 1 atm pressure is 28.80 cal K^–1.
(Given: heat of fusion is 80 cal g^–1)
The value of 'x' is:

The incorrect statement(s) among the following statements is/are -

1. (i), (iv)
2. (ii), (iv)
3. (iii), (iv)
4. (i), (iii)