Number of moles of given acid and base are
HNO3=1000600×0.2M=0.12molesNaOH=1000400×0.1M=0.04moles
Now neutralisation reaction between them will be
HNO3+NaOH→NaNO3+H2O0.12mole0.04mole0.08mole0mole0.04mole
Heat relesed during this reaction will be
ΔrH=0.04×(57×103)J
=2280J
Now temperature increased can be calculated by
mSΔT=2280J
⇒1000mL×mL1gm×4.2×ΔT=2280
ΔT=4.22280×10−3
=542.86×10−3
\Delta T=54.286\times {10}^{-2}^{\circ}C