| Assertion (A): | Helium is used to dilute oxygen in the diving apparatus. |
| Reason (R): | Helium has a high solubility in O2. |
| 1. | (A) is False but (R) is True. |
| 2. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 3. | Both (A) and (R) are True and (R) is not the correct explanation of (A). |
| 4. | (A) is True but (R) is False. |
| Assertion (A): | Metallic sodium dissolves in liquid ammonia giving a deep blue solution, which is paramagnetic. |
| Reason (R): | The deep blue solution is due to the formation of amide. |
| 1. | (A) is False but (R) is True. |
| 2. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 3. | Both (A) and (R) are True and (R) is not the correct explanation of (A). |
| 4. | (A) is True but (R) is False. |
| 1. | \( \sigma \text { 1s }<\sigma^* \text { 1s }<\sigma 2 s<\) \(\sigma^* 2 s<\left(\pi 2 p_x=\pi 2 p_y\right)<\) \(\left(\pi^* 2 p_x=\pi^* 2 p_y\right)<\sigma 2 p_z<\sigma^* 2 p_z\) |
| 2. | \( \sigma \text { 1s }<\sigma^* \text { 1s }<\sigma 2 s<\sigma^* 2 s<\) \(\left(\pi 2 p_x=\pi 2 p_y\right)< \) \(\sigma 2 p_z<\left(\pi^* 2 p_x=\pi^* 2 p_y\right)<\sigma^* 2 p_z \) |
| 3. | \( \sigma \text { 1s }<\sigma^* \text { 1s }<\sigma 2 s<\sigma^* 2 s<\sigma 2 p_z<\) \( \left(\pi 2 p_x=\pi 2 p_y\right)<\) \(\left(\pi^* 2 p_x=\pi^* 2 p_y\right)<\sigma^* 2 p_z \) |
| 4. | \( \sigma \text { 1s }<\sigma^* \text { 1s }\) \(<\sigma 2 s<\sigma^* 2 s<\sigma 2 p_z< \) \( \sigma^* 2 p_z<\left(\pi 2 p_x=\pi 2 p_y\right)<\) \(\left(\pi^* 2 p_x=\pi^* 2 p_y\right) \) |
| Assertion (A): | A reaction can have zero activation energy. |
| Reason (R): | The minimum amount of energy required by reactant molecules so that their energy becomes equal to threshold value, is called activation energy. |
| 1. | (A) is False but (R) is True. |
| 2. | Both (A) and (R) are True and (R) is the correct explanation of (A) |
| 3. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 4. | (A) is True but (R) is False. |
| 1. | 2. | ||
| 3. | 4. |
| A: | Atoms of all elements are composed of two fundamental particles. |
| B: | The mass of the electron is \(9.10939 \times 10^{-31} \mathrm{~kg} \text {. }\) |
| C: | All the isotopes of a given element show the same chemical properties. |
| D: | Protons and electrons are collectively known as nucleons. |
| E: | Dalton's atomic theory regarded the atom as an ultimate particle of matter. |
| 1. | B, C and E only | 2. | A, B and C only |
| 3. | C, D and E only | 4. | A and E only |
| 1. | \(n_m = l+2\) | 2. | \(l = {\dfrac{n_m -1} 2}\) |
| 3. | \(l= 2n_m +1\) | 4. | \(n_m = 2l^2 + 1 \) |
| A. | dipole - dipole forces |
| B. | dipole-induced dipole forces |
| C. | hydrogen bonding |
| D. | covalent bonding |
| E. | dispersion forces |