Question

question 15 (1 point)
consider the properties lab with the three tests for ionic and covalent substances. which substance would melt, partially dissolve in the solution, but produce a dim glow in the led bulb during a conductivity test?
ionic substance: mgcl₂
large covalent substance: sucrose (c₆h₁₂o₆)
covalent substance: o₂
covalent acid: citric acid (c₆h₈o₇)

Explanation:

• Ionic substances like \(MgCl_2\) fully dissociate in solution and have high melting points. When dissolved, they produce a strong electrolyte solution, so the LED would glow brightly, not dimly.
• Large covalent substances like sucrose (\(C_6H_{12}O_6\)) are non - electrolytes. They dissolve as molecules and do not conduct electricity (LED would not glow).
• \(O_2\) is a covalent substance that is a gas at room temperature. It does not melt under normal lab conditions (unless cooled to very low temperatures not typical in a basic lab) and is not soluble enough to conduct electricity.
• Covalent acids like citric acid (\(C_6H_8O_7\)) partially dissociate in solution (\(C_6H_8O_7

ightleftharpoons H^++C_6H_7O_7^-\)). They have relatively low melting points (compared to ionic solids). The partial dissociation means they produce a small number of ions, resulting in a dim glow in the LED during a conductivity test.

Answer:

Covalent Acid: Citric Acid (\(C_6H_8O_7\))