Which of the following reaction not shift for completion ?A RCOOH + NaHCO3 → RCOONa + H2CO3 B RCOOH + NaCl → RCOONa + HCl C RCOOH + Na → RCOONa + H2 D RCOOH + CH3C≡C–Na+ → RCOONa + CH3–C≡CH

To determine which of the given reactions does not shift for completion, let's analyze each reaction step by step:

A) RCOOH + NaHCO3 → RCOONa + H2CO3 In this reaction, a carboxylic acid (RCOOH) reacts with sodium bicarbonate (NaHCO3) to form a carboxylate salt (RCOONa) and carbonic acid (H2CO3). Carbonic acid is unstable and decomposes into water (H2O) and carbon dioxide (CO2). Therefore, this reaction will shift towards completion.

B) RCOOH + NaCl → RCOONa + HCl In this reaction, a carboxylic acid (RCOOH) reacts with sodium chloride (NaCl) to form a carboxylate salt (RCOONa) and hydrochloric acid (HCl). Hydrochloric acid is a strong acid and completely dissociates in water. Therefore, this reaction will also shift towards completion.

C) RCOOH + Na → RCOONa + H2 In this reaction, a carboxylic acid (RCOOH) reacts with sodium metal (Na) to form a carboxylate salt (RCOONa) and hydrogen gas (H2). Since hydrogen gas is a gas and escapes from the reaction mixture, this reaction will not shift towards completion.

D) RCOOH + CH3C≡C–Na+ → RCOONa + CH3–C≡CH In this reaction, a carboxylic acid (RCOOH) reacts with sodium acetylide (CH3C≡C–Na+) to form a carboxylate salt (RCOONa) and an alkyne (CH3–C≡CH). This reaction involves the formation of a new carbon-carbon bond and does not involve any volatile or unstable compounds. Therefore, this reaction will also shift towards completion.

Based on the analysis, the reaction that does not shift for completion is C) RCOOH + Na → RCOONa + H2.