Question

1. a bottle of cola has h⁺ = 6.3 × 10⁻⁴ m. what is its ph, and is it more or less acidic than coffee (ph = 5)?
2. ocean water has a typical ph of 8.1, but acidification drops it to 7.8. by what factor does h⁺ increase?
3. a swimming pool should have a ph between 7.2 and 7.8. if the current ph is 8.5, how much greater is the oh⁻ compared to pure water?
4. a household cleaner has oh⁻ = 0.015 m. what is the ph, and what common base is it similar to in strength?

Explanation:

Step1: Calculate pH of cola

pH = -log[H⁺] = -log(6.3×10⁻⁴) ≈ 3.2
Compare to coffee (pH=5): lower pH = more acidic

Step2: Find [H⁺] factor for ocean water

ΔpH = 8.1 - 7.8 = 0.3
Factor = 10^ΔpH = 10^0.3 ≈ 2

Step3: Calculate [OH⁻] ratio for pool water

Pure water: pH=7 → pOH=7 → [OH⁻]=1×10⁻⁷ M
Pool: pH=8.5 → pOH=5.5 → [OH⁻]=10⁻⁵.⁵ ≈ 3.16×10⁻⁶ M
Ratio = (3.16×10⁻⁶)/(1×10⁻⁷) ≈ 32

Step4: Calculate pH of cleaner

pOH = -log[OH⁻] = -log(0.015) ≈ 1.82
pH = 14 - 1.82 ≈ 12.2; similar to ammonia

Answer:

1. pH≈3.2, more acidic than coffee
2. Factor≈2
3. ~32 times greater
4. pH≈12.2, similar to ammonia strength