Match the following:
(i) Magnetic quantum number -(a) Optical isomerism
(ii) Boron halides -(b) Sodium carbonate
(iii) Lactic acid -(c) Orientation of the orbital
(iv) Solvay.s process -(d) Lewis acid.

Answer

To solve the matching question, we need to analyze each item in Table 1 and find its corresponding match in Table 2 based on their definitions and properties.

### Step-by-Step Solution:

1. **Magnetic Quantum Number (i)**:
- The magnetic quantum number (m_l) is associated with the orientation of orbitals in a subshell. It indicates the specific orbital within a subshell where an electron is likely to be found.
- **Match**: (i) Magnetic quantum number - **(c) Orientation of the orbital**.

2. **Boron Halides (ii)**:
- Boron halides, such as BF3 and BCl3, are known to be electron-deficient compounds. They do not have a complete octet and can accept electrons, thus behaving as Lewis acids.
- **Match**: (ii) Boron halides - **(d) Lewis acid**.

3. **Lactic Acid (iii)**:
- Lactic acid is a compound that contains a chiral carbon atom, which has four different groups attached to it. This property allows lactic acid to exhibit optical isomerism, where two enantiomers can exist.
- **Match**: (iii) Lactic acid - **(a) Optical isomerism**.

4. **Solvay's Process (iv)**:
- The Solvay process is an industrial method used to produce sodium carbonate (soda ash) from sodium chloride (brine), ammonia, and carbon dioxide. Therefore, it directly relates to the production of sodium carbonate.
- **Match**: (iv) Solvay's process - **(b) Sodium carbonate**.

### Final Matches:
- (i) Magnetic quantum number - (c) Orientation of the orbital
- (ii) Boron halides - (d) Lewis acid
- (iii) Lactic acid - (a) Optical isomerism
- (iv) Solvay's process - (b) Sodium carbonate

### Summary of Matches:
1. (i) - (c)
2. (ii) - (d)
3. (iii) - (a)
4. (iv) - (b)

---