Electrolyte Testing Type of Electrolyte Solution/Substance Observations (Strong, Weak, or Non)

Question

Electrolyte Testing Type of Electrolyte Solution/Substance Observations (Strong, Weak, or Non)

Isopropyl Alcohol - NON

0.1 M HCI - STRONG

0.1 M NaOH - STRONG

0.1 M CaCL2 - STRONG

0.1 M HC2H3O2 - WEAK

Isotonic Saline (0.15 M NaCl) - STRONG

Isotonic Glucose (0.30 M glucose) - NON

1. Classify the solutes in the following generic equations as a weak electrolyte, a strong electrolyte, or a non-electrolyte in water.

a. XY2 (s) - X2+ (aq) + 2Y-(aq) ______________

b. HX (aq) H+ (aq) + X- (aq) ______________

c. XYZ (s) - XYZ (aq) ______________

d. YOH (s) - Y+ (aq) + OH- (aq) ______________

2. For the solutes that were tested above, write an equation for their solution in water. Use the generic equations in question 1 above as a guide to help you. 

NaCl __________

CaCl2 _________

HC2H3O2 ___________

NaOH _____________

C6H12O6 ________________

Answer 1

1. a) strong   b) weak   c) non-electrolyte   d) strong

The single idea behind all four: an electrolyte classification is about whether the solute produces ions in water, and how completely. It is not about how well it dissolves. Glucose dissolves beautifully and conducts nothing at all.

a. XY₂(s) → X²⁺(aq) + 2Y^-(aq) - a solid breaking up completely into ions. Strong.

b. HX(aq) ⇌ H⁺(aq) + X^-(aq) - only partly ionised, so most of it stays as intact HX molecules. Weak.

c. XYZ(s) → XYZ(aq) - it dissolves, but the formula is unchanged on the right. No ions, nothing to carry current. Non-electrolyte.

d. YOH(s) → Y⁺(aq) + OH^-(aq) - complete dissociation into ions, a strong base. Strong.

Worth saying plainly: the arrows are what carry the answer in part 1. A single arrow means the reaction runs to completion, a double arrow means it stops at equilibrium with plenty of un-ionised solute left. That distinction is the whole difference between strong and weak, and it is the reason b is weak while a and d are strong even though all three produce ions. In the version posted here the arrows did not survive the formatting, but part 2 settles it anyway: the five substances listed there map one-to-one onto these four generic types, and the weak one in your data table is acetic acid, which is the HX case.

2. Equations for the tested solutes:

NaCl(s) → Na⁺(aq) + Cl^-(aq)   strong

CaCl₂(s) → Ca²⁺(aq) + 2Cl^-(aq)   strong - this is your generic type a, and note the 2 in front of the chloride

HC₂H₃O₂(aq) ⇌ H⁺(aq) + C₂H₃O₂^-(aq)   weak - type b, and the only one here that takes a double arrow

NaOH(s) → Na⁺(aq) + OH^-(aq)   strong - type d

C₆H₁₂O₆(s) → C₆H₁₂O₆(aq)   non-electrolyte - type c, the formula is identical on both sides

Two observations that tie this back to what you measured. The isotonic saline and the isotonic glucose have similar concentrations, yet only the saline lit the bulb - same amount of dissolved material, completely different conductivity, because only one of them makes ions. And your two 0.1 M acids, HCl and acetic acid, behave differently for the same reason: identical concentration, but HCl ionises completely and acetic acid barely does, which is exactly what strong versus weak means.