Carbon-14 labelled acetic acid, CH₃-¹⁴C(=O)-OH, is treated separately with two reagents.
CH₃¹⁴COOH + NaH $\to$ salt + gas A
CH₃¹⁴COOH + NaNH₂ $\to$ salt + gas B
If X is the sum of the molar masses of A and B, find the value of X - 15.

Question

Carbon-14 labelled acetic acid, CH₃-¹⁴C(=O)-OH, is treated separately with two reagents.

CH₃¹⁴COOH + NaH $\to$ salt + gas A

CH₃¹⁴COOH + NaNH₂ $\to$ salt + gas B

If X is the sum of the molar masses of A and B, find the value of X - 15.

TestHub · Accepted Answer

With NaH the acid releases hydrogen : gas A = H₂, molar mass 2. With NaNH₂ it releases ammonia : gas B = NH₃, molar mass 17. The ¹⁴C label stays behind in the carboxylate salt and does not enter either gas. X - 15 = 2 + 17 - 15 = 4.

Chemistry - GOC Question with Solution | TestHub

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