The mass fraction of carbon in the limiting aldehyde is 62.07%. Establish the molecular formula of the aldehyde.

1. Let’s write an expression for calculating the mass fraction of carbon using the general formula for aldehyde:
w (CnH2n + 1CHO) = (n + 1) * Ar (C): Mr (CnH2n + 1CHO);
2.we substitute the numerical values and calculate what the index n in the formula for the limiting aldehyde is equal to:
0.6207 = (n + 1) * 12: (12n + 2n + 1 + 12 + 1 + 16);
0.6207 = (12n + 12): (14n + 30);
8.6898n + 18.621 = 12n + 12;
3.3102n = 6.621;
n = 2;
3.we substitute the found number instead of the index and write the formula:
C2H5CHO.
Answer: propanal C2H5CHO.