The problem provides us with the following information:
- The balloon is ascending with an acceleration of 0.2 meters per second square.
- Two stones are dropped from the balloon at an interval of 2 seconds.
- We need to find the distance between the stones 1.5 seconds after the second stone is released.

To solve this problem, let's break it down into smaller steps:

1. Determine the time at which the second stone is released:
Since the stones are dropped at an interval of 2 seconds, we can calculate the time at which the second stone is released. If we assume the first stone is dropped at time t=0, then the second stone is released 2 seconds later at t=2.

2. Calculate the initial velocity of the stones:
The initial velocity of an object dropped from rest is always 0. Therefore, both stones have an initial velocity of 0 m/s.

3. Find the time at which we need to calculate the distance:
We are asked to find the distance between the stones 1.5 seconds after the second stone is released. This means we need to calculate the distance at t=2+1.5=3.5 seconds.

4. Calculate the distance covered by each stone:
To calculate the distance covered by each stone, we can use the equation:
distance = initial velocity * time + (1/2) * acceleration * time^2

For the first stone, the time is 3.5 seconds, the initial velocity is 0 m/s, and the acceleration is -9.8 m/s^2 (negative because it is in the opposite direction to the balloon's acceleration). Plugging in these values, we get:
distance1 = 0 * 3.5 + (1/2) * (-9.8) * (3.5)^2

For the second stone, the time is 1.5 seconds, the initial velocity is also 0 m/s, and the acceleration is -9.8 m/s^2. Plugging in the values, we get:
distance2 = 0 * 1.5 + (1/2) * (-9.8) * (1.5)^2

5. Calculate the distance between the stones:
To find the distance between the stones, we subtract the distance covered by the second stone from the distance covered by the first stone:
distance_between_stones = distance1 - distance2

By performing the calculations, we can determine the distance between the stones 1.5 seconds after the second stone is released.