What will be RQ of a substrate whose respiration equation is
`C_(4)H_(6)O_(5)+3O_(2)rarr4CO_(2)+3H_(2)O`

Options

A. 4/5=0.8
B. 5/4=1.25
C. 4/3=1.33
D. 3/4=0.75

Answer

To find the respiratory quotient (RQ) of the substrate given in the respiration equation \( C_{4}H_{6}O_{5} + 3O_{2} \rightarrow 4CO_{2} + 3H_{2}O \), we can follow these steps:

### Step 1: Understand the definition of RQ
The respiratory quotient (RQ) is defined as the ratio of the volume of carbon dioxide (CO₂) produced to the volume of oxygen (O₂) consumed during respiration. Mathematically, it is expressed as:
\[ RQ = \frac{\text{Volume of } CO_{2} \text{ produced}}{\text{Volume of } O_{2} \text{ consumed}} \]

### Step 2: Identify the amounts of CO₂ produced and O₂ consumed
From the given respiration equation:
- The amount of CO₂ produced is 4 moles (as indicated by the coefficient of CO₂).
- The amount of O₂ consumed is 3 moles (as indicated by the coefficient of O₂).

### Step 3: Substitute the values into the RQ formula
Now, we can substitute the values we identified into the RQ formula:
\[ RQ = \frac{4 \text{ moles of } CO_{2}}{3 \text{ moles of } O_{2}} = \frac{4}{3} \]

### Step 4: Calculate the RQ value
Calculating the RQ gives us:
\[ RQ = 1.33 \]

### Step 5: Identify the correct option
Among the options provided:
- \( \frac{4}{5} = 0.8 \) (incorrect)
- \( \frac{5}{4} = 1.25 \) (incorrect)
- \( \frac{4}{3} = 1.33 \) (correct)
- \( \frac{3}{4.75} \) (incorrect)

Thus, the correct answer is \( \frac{4}{3} \) or 1.33.