A glass beaker with water is placed inside a bell jar and the jar is subjected to vacuum. The room temperature was 27°C when the experiment was carried out. Initially the water was at atmospheric pressure inside the bell jar. After the vacuum pump was switched on, pressure inside the bell jar started going down. The water in the beaker began to boil when pressure in the bell jar reached x kPa. What is the numerical value of x? Explain your answer conceptually.