Chemistry - Redox Reactions Question with Solution | TestHub

With phenolphthalein, $\mathrm{N}{\mathrm{a}}_2\mathrm{C}{\mathrm{O}}_3$ is taken only to $\mathrm{NaHC}{\mathrm{O}}_3$: mol $\mathrm{N}{\mathrm{a}}_2\mathrm{C}{\mathrm{O}}_3$ = $0.5{\mathrm{V}}_1$, so molarity = $0.5{\mathrm{V}}_1/0.25$ = $2{\mathrm{V}}_1$ - (a) true, (c) false. With methyl orange, both are fully neutralized: mol $\mathrm{NaHC}{\mathrm{O}}_3$ = $0.5{\mathrm{V}}_2$ - $2(0.5{\mathrm{V}}_1)$ = $0.5({\mathrm{V}}_2$ - $2{\mathrm{V}}_1$), so molarity = $2({\mathrm{V}}_2$ - $2{\mathrm{V}}_1$) - (b) true, (d) false. Hence (a), (b).