At which temperature, vapour pressure of ethylalcohol will be maximum :-(1) 300 K (2) 98°C(3) 98 K (4) 50° C

To determine the temperature at which the vapor pressure of ethyl alcohol will be maximum, we need to consider the relationship between temperature and vapor pressure.

According to the Clausius-Clapeyron equation, the vapor pressure of a substance increases with increasing temperature. Therefore, we can eliminate options (3) and (4) since they have lower temperatures compared to options (1) and (2).

Now, let's compare options (1) and (2). Option (1) states a temperature of 300 K, while option (2) states a temperature of 98°C. To compare these temperatures, we need to convert 98°C to Kelvin.

To convert Celsius to Kelvin, we add 273.15 to the Celsius temperature. Therefore, 98°C + 273.15 = 371.15 K.

Comparing the temperatures, we can see that 371.15 K (option 2) is higher than 300 K (option 1). Since the vapor pressure of ethyl alcohol increases with increasing temperature, the temperature at which the vapor pressure will be maximum is 98°C (option 2).

Therefore, the correct answer is option (2) - 98°C.