JEE Main levelSingle correct optionDifficulty 2 of 3ia042
25.0 mL of 0.10 M HCl is mixed with 20.0 mL of 0.080 M NaOH. Use log2=0.301. The pH of the mixture is closest to
A1.44
B12.30
C1.70
D1.00
Answer: C
HCl =2.5 mmol and NaOH =1.6 mmol, so 0.9 mmol of HX+ remains in 45 mL: [HX+]=0.020 M =0.020 M. pH =2−log2=1.70. Dividing by 25 mL instead of 45 mL gives 1.44.