Calculate the concentration of H3O+ in a solution that contains 6.25 × 10-9 M OH- at 25°C. Identify the solution as acidic, basic, or neutral.

[OH⁻] = 1.60 × 10⁻⁶ M

Basic

Explanation:

Step 1: Given data

Concentration of H₃O⁺: 6.25 × 10⁻⁹ M

Step 2: Calculate the concentration of OH⁻

We will use the following expression.

Kw = [H₃O⁺] × [OH⁻] = 1.00 × 10⁻¹⁴

[OH⁻] = 1.00 × 10⁻¹⁴ / 6.25 × 10⁻⁹ = 1.60 × 10⁻⁶ M

Step 3: Calculate the pH

We will use the following expresion.

pH = -log [H₃O⁺] = -log (6.25 × 10⁻⁹) = 8.20

Since the pH > 7, the solution is basic.

alkaline metals are lithium, sodium, rubidium, potassium, cesium and francium.

alkali metals have electronegativity from 0.7 to 1, lowest in periodic table of elements, which means that alkali metals (i group in periodic table) has positive oxidation number in compounds.

electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

alkaline metals (far left in main group) have lowest ionizations energy and easy remove valence electrons,

for example, potassium is the alkali metal and has a single valence electron in the outer electron shell.

electron configuration of potassium is: ₁₉k 1s²2s²2p⁶3s²3p⁶4s¹.

they can not exist alone in nature, because they are very reactive.

the atomic number will stay the same no matter how many electrons it has, so it doesn’t decrease nor increase. it’ll only change with a different number of protons