Which of the following compounds is the most soluble in water? A. CH3CH2OH B. CH3CH2CH2OH C. CH3OH D. CH3CH2CH2CH2OH E. CH3CH2CH2CH2CH2OH What is the general formula for alkenes? A. CnHn+2 B. CnHZn+2 C. CnHZn D. CnHZn-2 E. CnHn-2 Which organic compound is saturated? A. pentane B. ethylpentyne C. benzene D. cyclohexyne E. pentene
The Correct Answer and Explanation is:
. Which of the following compounds is the most soluble in water?
- Answer: C. CH3OH (Methanol)
Explanation:
Solubility in water depends on the ability of a compound to form hydrogen bonds with water molecules. The more hydrogen bonding a molecule can form, the more soluble it is in water. Here’s a breakdown of each compound:
- A. CH3CH2OH (Ethanol): Ethanol has an -OH (hydroxyl) group, which can form hydrogen bonds with water. It is highly soluble in water, but it is less soluble than methanol due to its larger hydrophobic ethyl group (CH2CH3).
- B. CH3CH2CH2OH (Propanol): Propanol also has a hydroxyl group that can hydrogen bond with water. However, the longer hydrophobic chain makes it less soluble in water than ethanol.
- C. CH3OH (Methanol): Methanol is the simplest alcohol with a hydroxyl group (-OH) and is the most soluble in water because its small size allows it to form strong hydrogen bonds with water.
- D. CH3CH2CH2CH2OH (Butanol): Butanol, while able to form hydrogen bonds, has a longer hydrophobic chain and is less soluble in water compared to the smaller alcohols.
- E. CH3CH2CH2CH2CH2OH (Pentanol): Pentanol is less soluble in water because of its larger hydrophobic part.
Methanol is the most soluble due to its smaller molecular size and higher capacity to form hydrogen bonds with water.
2. What is the general formula for alkenes?
- Answer: E. CnH2n
Explanation:
Alkenes are hydrocarbons that contain at least one double bond between carbon atoms. The general formula for alkenes is CnH2n, where “n” represents the number of carbon atoms in the molecule. This formula accounts for the two hydrogen atoms that are typically lost due to the presence of a carbon-carbon double bond, compared to alkanes, which follow the formula CnH2n+2.
Let’s go over the other options:
- A. CnHn+2: This is the formula for alkanes (saturated hydrocarbons), not alkenes.
- B. CnHZn+2: This is incorrect as it doesn’t follow the structure of alkenes or any typical organic compounds.
- C. CnHZn: This is not a correct formula for any hydrocarbons.
- D. CnHZn-2: This formula is incorrect and doesn’t represent alkenes.
Thus, the correct formula is CnH2n for alkenes.
3. Which organic compound is saturated?
- Answer: A. Pentane
Explanation:
Saturated compounds are those in which all carbon-carbon bonds are single bonds, meaning they contain the maximum possible number of hydrogen atoms. Let’s analyze the options:
- A. Pentane (C5H12): Pentane is a straight-chain alkane with all single bonds between carbon atoms, making it saturated.
- B. Ethylpentyne: This compound contains a triple bond (as suggested by the “yne” suffix, indicating alkyne), making it unsaturated.
- C. Benzene (C6H6): Benzene has a ring structure with alternating single and double bonds, making it unsaturated.
- D. Cyclohexyne: The “yne” suffix suggests a triple bond, indicating this is an unsaturated compound.
- E. Pentene (C5H10): Pentene contains a double bond, which makes it an unsaturated compound.
So, pentane is the saturated compound because it contains only single bonds between carbon atoms.
In summary:
- Most soluble in water: C. CH3OH (Methanol)
- General formula for alkenes: E. CnH2n
- Saturated compound: A. Pentane
