Master Mnemonics for INC-03

1. Contact Process Steps: "SO2 Stops, Oleum Outperforms"

• S → SO2 (Step 1: Start burning sulfur)
• SO2 → SO3 (Step 2: Oxidize with V2O5)
• SO3 → Oleum (Step 3: Oleum forms in conc. H2SO4)
• Oleum → H2SO4 (Step 4: Output after dilution)

2. "SO3 Stays in Sulfuric, Never Naked in Water" → SO3 is dissolved in concentrated H2SO4 (not water) to form oleum. If dissolved in water → acid mist.

3. Halogen Oxidizing Power: "Fierce Cats Bite Individually"

• F2 > Cl2 > Br2 > I2 (F = Fierce, C = Cats, B = Bite, I = Individually)
• Or: "F Can Beat Iodine" — decreasing oxidizing power

4. Oxoacid Strength: "More O, More Acidic"

• HOCl (+1, 1 extra O) → Weakest
• HClO4 (+7, 4 extra O) → Strongest
• Rule: Count the O atoms (not counting the OH oxygen) — more O = stronger acid

5. Xenon Compound Lone Pairs: "Six, Four, Two"

• XeF2: 3 lone pairs (total $e^{-}$ pairs = 5)
• XeF4: 2 lone pairs (total $e^{-}$ pairs = 6)
• XeF6: 1 lone pair (total $e^{-}$ pairs = 7) → Or: "Lone pairs decrease by 1 as F increases by 2"

6. XeF2 is Linear: "Two Axes, Three Equators"

• 3 lone pairs → Equatorial (the equator has 3 positions in TBP)
• 2 F atoms → Axial (linear, 180°)
• "3 equatorial lone pairs push F to the poles (axial) → Linear"

7. HF is Weakest HX Acid: "Short Chain, Strong Link"

• Shortest H-X bond → Strongest bond → Hardest to break → Weakest acid
• HF = Short + Strong = Hard to ionize = Weak acid
• HI = Long + Weak = Easy to ionize = Strong acid

8. Interhalogen Shapes: "L-T-SP-PBP"

• AB = Linear (diatomic)
• AB3 = T-shaped (T-shirt has 3 corners!)
• AB5 = Square Pyramidal (5-sided pyramid has square base)
• AB7 = Pentagonal Bipyramidal (PBP — 7 = penta + 2 poles)