Chemistry - Redox Reactions Question with Solution | TestHub

I is correct: methyl orange signals full neutralization ($\mathrm{N}{\mathrm{a}}_2\mathrm{C}{\mathrm{O}}_3$ $\to$ ${\mathrm{H}}_2\mathrm{C}{\mathrm{O}}_3$), so 2 mol $\mathrm{HCl}$ per mol of $\mathrm{N}{\mathrm{a}}_2\mathrm{C}{\mathrm{O}}_3$. II is incorrect: with phenolphthalein the end point comes at the $\mathrm{NaHC}{\mathrm{O}}_3$ stage, where only 1 mol of $\mathrm{HCl}$ per mol of $\mathrm{N}{\mathrm{a}}_2\mathrm{C}{\mathrm{O}}_3$ is consumed. Hence (c).