Problem: A student tests four solids for their ability to complete an electrical circuit when dissolved in water by observing their ability to close a circuit containing a light bulb and obtains the following results: Solid          Concentration (M)         Strength of light emittedA                0.20                                BrightB                0.20                                Dim C                0.20                                NoneD                0.20                                BrightWhich of the solids is a weak electrolyte when dissolved in water? Check all that apply.

FREE Expert Solution

We’re being asked to determine which of the given solids is the weak electrolyte given their relative electrical conductivity.

Conductivity in aqueous solutions is a measure of the ability of water to conduct an electric current. The more ions there are in the solution, the higher its conductivity.

• Strong electrolytes: dissociate completely in water; include soluble ionic salts, strong acids, and bases

a. Ionic salts: those that follow the rules of being soluble in solubility rules

b. Strong acids: HCl, HBr, HI, HNO3, H2SO4, HClO4, HClO3

c. Strong bases: Group 1A and 2A (Ca and lower) metals paired with OH, H, O2–, or NH2

• Weak electrolytes: doesn’t dissociate completely in water; include weak acids and bases

a. Weak acids: include HF, HC2H3O2, HNO2, H2CO3, H3PO4

b. Weak bases: Be(OH)2, Mg(OH)2, NH3, NH4OH

Strong electrolytes are good conductors of electricity and weak electrolytes are weak conductors of electricity.

• Nonelectrolytes: doesn’t dissociate at all; include molecular compounds

a. Alcohols: composed of carbon and hydrogen with a –OH group

b. Sugars: for example C6H12O6 (glucose) and C12H22O11 (sucrose)

c. Water (H2O)

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Problem Details

A student tests four solids for their ability to complete an electrical circuit when dissolved in water by observing their ability to close a circuit containing a light bulb and obtains the following results:

Solid          Concentration (M)         Strength of light emitted

A                0.20                                Bright

B                0.20                                Dim

C                0.20                                None

D                0.20                                Bright

Which of the solids is a weak electrolyte when dissolved in water? Check all that apply.