To determine which of the given compounds are Lewis acids, we need to recall that a Lewis acid is defined as a substance that can accept an electron pair. Let’s analyze each option:
- a) CH3CH2OH: This is ethanol, which has a hydroxyl group. While it can act as a weak acid, it does not typically accept electron pairs and is not considered a Lewis acid.
- b) S2: This refers to the disulfur molecule. S2 itself is not known to behave as a Lewis acid; it is more commonly involved in bond formation rather than accepting electrons.
- c) BeCl2: Beryllium chloride can indeed act as a Lewis acid. In this compound, the beryllium atom has an incomplete octet and can accept electron pairs from Lewis bases.
- d) CH3CH2+: This is a carbocation. Since it has a positive charge, it is electron-deficient and can readily accept electrons. Thus, it behaves as a Lewis acid.
Based on this analysis, the compounds that act as Lewis acids among the options given are c) BeCl2 and d) CH3CH2+.