Question

20mL of 0.5 M HCl and 35 mL of 0.1 N NaOH are mixed. The resulting solution will
A. be neutral
B. be basic
C. turn phenolphthalein
D. turn methyl orange solution red

Answer 1

Correct Answer - D
0.5 HCl `=0.5 M HCl`
0.1 N NaOH `=0.1 ` MNaOH ltBRgt `HCl +NaOH rarr M xx V = 0.5 xx 20 xx 10^(-3)`
`=10^(-2)`
Moles of NaOH `=M xx V =0.1 xx 35 xx 10^(-3)`
`=3.5 xx 10^(-3)`
As the solutions on mixing will contains excess of HCl `(10^(-2) gt 3.5 xx 10^(-3))`, it will turn methyl orange red.