In a reaction, when the concentration of reactant is increased two times, the increase in rate of reaction was four times. Order of reaction is:

Options

A. zero
B. 1
C. 2
D. 3

Explanation

To determine the order of the reaction based on the given information, we can use the relationship between the concentration of reactants and the rate of reaction. Here’s the step-by-step solution:

### Step 1: Understand the relationship between concentration and rate
The rate of a reaction can be expressed as:
\[ \text{Rate} = k [A]^n \]
where:
- \( k \) is the rate constant,
- \( [A] \) is the concentration of the reactant,
- \( n \) is the order of the reaction.

### Step 2: Analyze the given information
From the problem, we know:
- The concentration of the reactant \( [A] \) is increased two times, i.e., \( [A] \) changes from \( [A] \) to \( 2[A] \).
- The rate of reaction increases four times.

### Step 3: Set up the equation for the initial and new rates
Let the initial rate of reaction be \( R_1 \) when the concentration is \( [A] \):
\[ R_1 = k [A]^n \]

When the concentration is doubled, the new rate \( R_2 \) becomes:
\[ R_2 = k (2[A])^n = k \cdot 2^n \cdot [A]^n \]

### Step 4: Relate the two rates
According to the problem, the new rate \( R_2 \) is four times the initial rate \( R_1 \):
\[ R_2 = 4R_1 \]

Substituting the expressions for \( R_1 \) and \( R_2 \):
\[ k \cdot 2^n \cdot [A]^n = 4 \cdot k [A]^n \]

### Step 5: Simplify the equation
We can cancel \( k \) and \( [A]^n \) from both sides (assuming \( [A] \neq 0 \)):
\[ 2^n = 4 \]

### Step 6: Solve for \( n \)
Now, we can solve for \( n \):
\[ 2^n = 2^2 \]
This implies:
\[ n = 2 \]

### Conclusion
The order of the reaction is **2**.

---