Question

Alanine, the amino acid the respective structure at $pH=2$ and $pH=10$ will be

• A. $N{H}_2-\stackrel{\underset{|}{C}{H}_3}{\mathrm{CH}}-CO{O}^{-}$, $H_3\stackrel{+}{N}-\stackrel{\underset{|}{C}{H}_3}{\mathrm{CH}}-COOH$
• B. $H_3\stackrel{+}{N}-\stackrel{\underset{|}{C}{H}_3}{\mathrm{CH}}-COO,H_3\stackrel{+}{N}-\stackrel{\underset{|}{C}{H}_3}{\mathrm{CH}}-COOH$
• C. $H_3\stackrel{+}{N}-\stackrel{\underset{|}{C}{H}_3}{\mathrm{CH}}-COOH,N{H}_2-\stackrel{\underset{|}{C}{H}_3}{\mathrm{CH}}-CO{O}^{\ominus }$
• D. $N{H}_2-\stackrel{\underset{|}{C}{H}_3}{\mathrm{CH}}-CO{O}^{-},H_3\stackrel{+}{N}-\stackrel{\underset{|}{C}{H}_3}{\mathrm{CH}}-COO$

Answer 1

Answer: (C)

At $P_H=2:H_3{N}^{+}-\stackrel{\underset{|}{C}{H}_3}{\mathrm{CH}}-COOH$
At $P_H=10:N{H}_2-\stackrel{\underset{|}{C}{H}_3}{\mathrm{CH}}-CO{O}^{-}$