Question 4 of 37intermediate🔧 ApplyShort Answer2 marks

The conversion of molecules XX to YY follows second order kinetics. If concentration of XX is increased to three times how will it affect the rate of formation of YY?

Correct Answer

For a second order reaction, the rate law is given by:

Rate = k[X]²

When the concentration of X is increased to three times, the new concentration becomes 3[X]. Substituting this in the rate equation:

New Rate = k[3X]² = k × 9[X]² = 9 × k[X]²

Therefore, the rate of formation of Y will increase by 9 times (or becomes nine times the original rate).

Exercise: Intext Questions | Q: 3.4 | (Page 11)
For More Understanding

Explanation

This question tests understanding of how reaction rate depends on concentration for different orders. For a second order reaction, the rate is proportional to the square of the concentration of the reactant. When concentration is tripled (3 times), the rate increases by (3)² = 9 times. The textbook context shows similar examples where rate depends on square of concentration (like NO in the example given).

Solution Steps

  1. Step 1: Write the rate law for second order reaction: Rate = k[X]²

  2. Step 2: Substitute new concentration (3[X]) into the rate equation: New Rate = k[3X]²

  3. Step 3: Simplify: New Rate = k × 9[X]² = 9 × k[X]² = 9 × original rate

  4. Step 4: Conclude that rate increases by 9 times.