Charles's Law-

Where:-
- V₁ = Initial volume
- T₁ = Initial temperature
- V₂ = Final volume
- T₂ = Final temperature
As per question, we are given that -
- V₂ =175 mL
- T₁ = 50°C
- T₂ = 150°C
We are given the initial temperature and the final temperature in °C.So, we first have to convert those temperatures in Celsius to kelvin by adding 273-
= 50+ 273 = 323K
=150+273 = 423K
Now that we have obtained all the required values, so we can put them into the formula and solve for V₁:-






Therefore, the original volume ( Initial volume) of neon is 133.63mL.