Answer : The new absolute pressure is, 
Explanation :
Gay-Lussac's Law : It is defined as the pressure of the gas is directly proportional to the temperature of the gas at constant volume and number of moles.
or,
where,
= initial pressure of gas
= final pressure of gas
= initial temperature of gas = 
= final temperature of gas = 
Now put all the given values in the above equation, we get:
Therefore, the new absolute pressure is,
The unit M means that mole/L, So first change the unit of solution volume to L which is 0.25 L. So the mole of solute is 2.5*0.25=0.625 mol.
<u><em>Answer:</em></u>
- The correct answer is a.
- The ratio of their masses is always the same
<u><em>Explanation:</em></u>
- Dalton law was based on law of conservation of masses and law of conservation definite proportional. So here , it is cleared that the ratio of their masses should be always same.
0.50 Molar means 0.50 moles/liter
(.5 moles/liter)/3.5 moles= 1/7 Liters
