Match the following
`{:((A),"vapour density ",(p),"unit cells"),((B),"1 mol ",(q),6.023xx 10^(23)"electrons"),((C),"12 g carbon",(r),6.023 xx 10^(23)"atoms"),((D),96500 C,(s),1/2 xx "Molecular mass "),(,,(t),22.4 " litre at STP"):}`

Answer

To solve the matching question, we need to analyze each item and find the correct pairings based on the definitions and relationships in chemistry.

### Step-by-Step Solution:

1. **Identify the first item: Vapour Density (A)**
- Vapour density is defined as the mass of a certain volume of gas compared to the mass of an equal volume of hydrogen at the same temperature and pressure. It is also related to molecular mass by the formula:
\[ \text{Vapour Density} = \frac{1}{2} \times \text{Molecular Mass} \]
- Therefore, Vapour Density (A) matches with (S) which is "1/2 x Molecular mass".

2. **Identify the second item: 1 mol (B)**
- One mole of any substance contains Avogadro's number of entities (atoms, molecules, etc.), which is approximately \(6.023 \times 10^{23}\).
- This means 1 mol (B) matches with (R) which is "6.023 x 10^(23) atoms" and also with (T) which is "22.4 litre at STP" (Standard Temperature and Pressure).

3. **Identify the third item: 12 g Carbon (C)**
- 12 grams of carbon corresponds to 1 mole of carbon, which also equals \(6.023 \times 10^{23}\) atoms.
- Therefore, 12 g Carbon (C) matches with (R) which is "6.023 x 10^(23) atoms".

4. **Identify the fourth item: 96500 C (D)**
- The value 96500 C is the charge equivalent to 1 mole of electrons, which is also equal to \(6.023 \times 10^{23}\) electrons.
- Thus, 96500 C (D) matches with (Q) which is "6.023 x 10^(23) electrons".

### Final Matching:
- A - S (Vapour Density - 1/2 x Molecular mass)
- B - R, T (1 mol - 6.023 x 10^(23) atoms and 22.4 litre at STP)
- C - R (12 g Carbon - 6.023 x 10^(23) atoms)
- D - Q (96500 C - 6.023 x 10^(23) electrons)

### Summary of Matches:
- A → S
- B → R, T
- C → R
- D → Q