sub90 ESATsub90 ESAT
Sign InStart Pace Check
sub90 ESATsub90 ESAT SyllabusARCH-C-11
Full Lesson Practice Questions →
UAT-UK SPEC: C12MODULE: CHEMISTRYTOPIC ID: ARCH-C-11

Molten vs. Aqueous Electrolysis Discharge Competition & Electron Mole Stoichiometry

Master Molten vs. Aqueous Electrolysis Discharge Competition & Electron Mole Stoichiometry on the ESAT Chemistry paper. Traditional classroom derivations waste valuable seconds. Using the 2-step Sub-90 invariant elimination method compresses solve time to 35s, saving +100s per question.

Standard Classroom Time
135s
Textbook multi-line derivations bleed exam clock
Sub-90 Target Pace
35s
Comfortably below the 88.8s per-question limit
Time Saved for Review
+100s
Banks clock buffer across 27 questions

2-Step Sub-90 Shortcut Formula

How to eliminate intermediate algebra and solve under 45 seconds.

Launch Interactive Lesson
STEP 1 • SETUP INVARIANT (LINE 1)10–15s
Line 1 (Molten == No Water): Only Na+/Cl−  ⟹  Na\text{Na}^+/\text{Cl}^- \implies \text{Na} (cathode) and Cl2\text{Cl}_2 (anode).

Establish the structural invariant and eliminate impossible options immediately.

STEP 2 • FAST SOLVE (LINE 2)15–25s
Line 2 (Conc. Aqueous): Na>H\text{Na} > \text{H} in reactivity   ⟹  H2\implies \text{H}_2 at cathode; conc. halide   ⟹  Cl2\implies \text{Cl}_2 at anode (20s).

Evaluate the simplified expression using integer factoring or unit elimination.

Distractor Trap Forensics

The predictable cognitive traps engineered by examiners into the wrong options.

TRAP #1multi_statement_linchpin_foil

Predicting sodium/magnesium metal at the cathode during electrolysis of AQUEOUS NaCl/MgSO4 (instead of H2 gas)

In aqueous solution, metals above hydrogen in the reactivity series stay in solution while H+ is reduced to H2.

Sub-90 Fix: Test invariants before expanding equations.
TRAP #2multi_statement_linchpin_foil

Predicting SO₄²⁻ or NO3⁻ discharge at the anode instead of O2 gas from 4OH⁻ -> O2 + 2H2O + 4e⁻

Sulfate and nitrate ions are never discharged in aqueous electrolysis; OH⁻ is oxidised to O2 unless a concentrated halide (Cl⁻, Br⁻, I⁻) is present.

Sub-90 Fix: Test invariants before expanding equations.
TRAP #3factor_of_two_or_stoichiometry_trap

Assuming equal moles of Al (Al³⁺ + 3e⁻), Cu (Cu²⁺ + 2e⁻), and Ag (Ag⁺ + e⁻) are deposited by the same charge Q

For fixed electron moles n(e⁻), moles of metal deposited is n(e⁻)/z (so Ag : Cu : Al = 1 : 1/2 : 1/3).

Sub-90 Fix: Test invariants before expanding equations.

Try 1 Timed Question: Molten vs. Aqueous Electrolysis Discharge Competition & Electron Mole Stoichiometry

Experience the Pearson VUE exam simulator with live split stopwatch.

Full Lesson All 15 Questions (ARCH-C-11)
sub90 ESAT Stopwatch Emblemsub90 ESAT
ARCH-C-11: Molten vs. Aqueous Electrolysis Discharge Competition & Electron Mole Stoichiometry (Sample)Chemistry
00:00.0
SUB-90 ZONE (<30S)
0.0s30s Sub-9090s ESAT Budget150s Classroom
Question 1 of 1ARCH-C-11 (6-Card Lesson)Format: Table-Row Matching
1-5Choose•FFlag•SScratchpad•EnterNext
Question 1 of 1 • 90s Target

Ready to Start Question 1?

The question stem, diagram, and answer options are hidden behind this pre-start gate. When you click below, the question will reveal and your 90-second split stopwatch will immediately begin ticking.

Chemistry•ARCH-C-11•Table-Row Matching
or press Enter to start
TOPIC MASTERY

Lock in Molten vs. Aqueous Electrolysis Discharge Competition & Electron Mole Stoichiometry with 15 Dedicated Questions

Solve full-length questions from our verified question bank, review distractor traps, and verify your pace.

Start Practice Drill →View Specification C12 Guide