Acetylene has two C-H groups

1.) Acetylene has two C-H groups. It will have two C-H stretching frequencies, the in-phase and out-of-phase stretching modes. The in-phase (symmetric) stretch occurs at 3374/cm and the out-of-phase stretch at 3333/cm. Explain why the in-phase vibration is located at a higher frequency than the out-of-phase stretch in the case of acetylene.

2.) Explain how mass effects act to lower the carbonyl frequency, as well as how inductive and hyperconjugation effects act to raise the carbonyl frequency of aldehydes relative to ketones.