Butanedioic acid is found in amber, algae, lichens, sugar cane and beets. It can be prepared in two stages starting from 1,2-dibromoethane. $\text{BrCH}_2\text{CH}_2\text{Br} \xrightarrow{\text{step 1}} X \xrightarrow{\text{step 2}} \text{HO}_2\text{CCH}_2\text{CH}_2\text{CO}_2\text{H}$ Which reagents could be used for this synthesis?
- Astep 1: HCN(g); step 2: HCl(aq)
- Bstep 1: HCO$_2$Na(aq); step 2: HCl(aq)
- Cstep 1: KCN(aq/alcoholic); step 2: H$_2$SO$_4$(aq)
- Dstep 1: NaOH(aq); step 2: K$_2$Cr$_2$O$_7$/H$_2$SO$_4$(aq)