against at -20 degree centigrade occupied the volume of one 40 ml calculate the temperature at which the volume of cash pickup 65ml pressure remain constant

The final temperature :T₂=411.125 K = 138.125 °C

Given

T₁=-20 °C+273 = 253 K

V₁=40 ml

V₂=65 ml

Required

Final temperature

Solution

Charles's Law  

When the gas pressure is kept constant, the gas volume is proportional to the temperature  

Input the value :

T₂=(V₂.T₁)/V₁

T₂=(65.253)/40

T₂=411.125 K = 138.125 °C

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)