Bond Angles in Compound X

The given question states that all bond angles in compound X are exactly 109.28 degrees. We need to determine the identity of compound X from the given options: chloroform, chloromethane, carbon tetrachloride, or iodoform.

Understanding Bond Angles

Bond angles are the angles formed between two adjacent bonds in a molecule. These angles are determined by the repulsion between electron pairs around the central atom. In a molecule with four electron pairs around the central atom, such as in compound X, the ideal bond angle is 109.28 degrees. This arrangement is known as tetrahedral geometry.

Analysis of Options

Let's analyze each option and check if it matches the given bond angle of 109.28 degrees:

a) Chloroform (CHCl3):
Chloroform has a central carbon atom surrounded by three hydrogen atoms and one chlorine atom. In this molecule, the carbon atom has four electron pairs and adopts a tetrahedral geometry. The bond angles in chloroform are approximately 109.5 degrees, which is close to the given bond angle but not exactly 109.28 degrees.

b) Chloromethane (CH3Cl):
Chloromethane also has a central carbon atom surrounded by three hydrogen atoms and one chlorine atom. Similar to chloroform, the carbon atom in chloromethane adopts a tetrahedral geometry. The bond angles in chloromethane are approximately 109.5 degrees, which is not exactly 109.28 degrees.

c) Carbon Tetrachloride (CCl4):
Carbon tetrachloride has a central carbon atom surrounded by four chlorine atoms. The carbon atom in carbon tetrachloride adopts a tetrahedral geometry, with bond angles of exactly 109.28 degrees. This matches the given bond angle, making carbon tetrachloride the correct answer.

d) Iodoform (CHI3):
Iodoform has a central carbon atom surrounded by three hydrogen atoms and one iodine atom. The carbon atom in iodoform also adopts a tetrahedral geometry, but the bond angles in iodoform are approximately 109.5 degrees, not exactly 109.28 degrees.

Conclusion

From the analysis above, we can conclude that compound X is carbon tetrachloride (CCl4) because it is the only option that matches the given bond angle of 109.28 degrees.