Question

question 2 (10 points) according to the vsepr model, which molecule is predicted to be linear? a) hcn b) so3 c) h2co d) h2s e) bf3

Explanation:

To determine which molecule is linear using VSEPR theory, we analyze each option:

Step 1: Analyze HCN (Option A)

HCN has a central C atom bonded to H (single bond) and N (triple bond). The central C has 2 bonding regions (no lone pairs). According to VSEPR, 2 bonding regions correspond to a linear geometry (bond angle \(180^\circ\)).

Step 2: Analyze \(SO_3\) (Option B)

\(SO_3\) has a central S atom bonded to 3 O atoms (double bonds). The central S has 3 bonding regions (no lone pairs), leading to a trigonal planar geometry (bond angle \(120^\circ\)), not linear.

Step 3: Analyze \(H_2CO\) (Option C)

\(H_2CO\) (formaldehyde) has a central C atom bonded to 2 H atoms (single bonds) and 1 O atom (double bond). The central C has 3 bonding regions, resulting in a trigonal planar geometry, not linear.

Step 4: Analyze \(H_2S\) (Option D)

\(H_2S\) has a central S atom bonded to 2 H atoms. The central S has 2 bonding regions and 2 lone pairs. VSEPR predicts a bent (angular) geometry (like \(H_2O\)), not linear.

Step 5: Analyze \(BF_3\) (Option E)

\(BF_3\) has a central B atom bonded to 3 F atoms. The central B has 3 bonding regions (no lone pairs), leading to a trigonal planar geometry, not linear.

Answer:

A. HCN