An aldehyde function is attached to a saturated unbranched cycle.
$2.24\;$ g of the substance $A$ react with excess Tollens reagent in basic medium.
Deposition of metallic silver with a mass of $4.316\;g$ is obtained.
1) Calculate the molar mass of the aldehyde.
2) Identify it!
$ n(Ag)$ $=$ $\frac{4.316}{107.9}$ $=$ $0.0400\; mol$
One mole aldehyde gives two moles silver.
$ n_A$ $=$ $\frac{0.0400}{2}$ $=$ $0.0200\; mol$
$M_A$ $=$ $\frac{2.24}{0.0200}$ $=$ $112\frac{g}{mol}$
One cycle, one double bond, therefore:
General formula:
$C_nH_{2n-2}O$
$12n$ $+$ $2n$ $-$ $2$ $+$ $16$ $=$ $112$
$n=7$
Molecular formula:
$C_7H_{12}O$
$A$ is cyclohexylmethanal also called (God knows why?) cyclohexylcarbaldehyde.
$A$ is cyclohexylmethanal also called (God knows why?) cyclohexylcarbaldehyde.