Question

student name: date: block: duration: 45 mins total marks: 100 read each question carefully and circle the correct answer (a, b, c o 1. the polarity of a water molecule is caused by __________. a. equal sharing of electrons b. unequal sharing of electrons between hydrogen and oxygen c. the same electronegativity of both atoms d. the circular motion of molecules

Explanation:

• In a water molecule (\(H_2O\)), oxygen is more electronegative than hydrogen.
• Electronegativity is the ability of an atom to attract electrons in a chemical bond.
• Due to the difference in electronegativity, the electrons in the \(O - H\) bonds are not shared equally.
• Oxygen pulls the electrons closer to itself, creating a partial negative charge (\(\delta-\)) on the oxygen atom and partial positive charges (\(\delta+\)) on the hydrogen atoms. This unequal sharing of electrons leads to the polarity of the water molecule.
• Option A: Equal sharing of electrons would result in a non - polar molecule. Since oxygen and hydrogen have different electronegativities, electrons are not shared equally in \(H_2O\), so A is incorrect.
• Option C: Oxygen (\(O\)) has an electronegativity of approximately \(3.44\) and hydrogen (\(H\)) has an electronegativity of approximately \(2.20\). They do not have the same electronegativity, so C is incorrect.
• Option D: The circular motion of molecules is not related to the polarity of the water molecule. Polarity is a result of charge separation due to electron distribution in the molecule, so D is incorrect.

Answer:

B. Unequal sharing of electrons between hydrogen and oxygen