According to Gay's Lussac law, we know, at constant Volume, Pressure is directly proportional to temperature.
So, P/T = constant
P₁/t₁ = P₂/t₂
P₁t₂ = P₂t₁
Here, we have: P₁ = 2.10 atm
P₂ = ?
T₁ = 21+273 = 294 K
T₂ = 98+273 = 371 K
Substitute their values into the expression:
2.10 × 371 = 294 × P₂
P₂ = 779.1 / 294
P₂ = 2.65 atm
In short, your final answer would be 2.65 atm
Hope this helps!