What is the pH of 500 mL of water after the addition of 1 mL of 2M NaOH?

pH = 11.60

Explanation:

When we add a base, we are increasing [OH⁻], so the pH will be totally basic.

pH of water = 7

Basic pH > 7

We are adding 2 M . 1 mL = 2 mmoles

2 mmoles of OH⁻ are contained in 501 mL of total volume.

[OH⁻] = 2 mmol / 501 mL =  3.99×10⁻³ M

- log 3.99×10⁻³ M = 2.39 → pOH

pH = 14 - pOH → 11.61

Water equilibrium

2H₂O  ⇄  H₃O⁺   +  OH⁻          Kw = 1×10⁻¹⁴

NaOH  →  Na⁺   +  OH⁻

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.

the answer to this question is 3.