What controls how fast and how much solute dissolves?

The rate of dissolving a solid is increased by stirring, heating and increasing surface area (smaller pieces). Solubility, the maximum that dissolves at a given temperature, is a separate idea changed by temperature: for most solids it rises with temperature, while gases become less soluble as temperature rises. Whether a solute dissolves at all follows like dissolves like: polar and ionic solutes dissolve in polar water, nonpolar solutes in nonpolar solvents.

How do I calculate molarity and dilute a solution?

Molarity is moles of solute per liter of solution, $M = \text{moles} / \text{liters}$, so moles equal molarity times volume in liters. To dilute, add solvent without changing the moles, so $M_1 V_1 = M_2 V_2$ relates the concentrated and diluted solutions. Always use liters (or keep volumes as a consistent ratio) and the volume of the whole solution, not just the solvent.

What are the definitions of acids and bases?

An Arrhenius acid produces hydrogen ions in water and an Arrhenius base produces hydroxide ions. In Bronsted-Lowry terms, an acid donates a proton and a base accepts one. Acids taste sour, turn blue litmus red and react with active metals; bases taste bitter, feel slippery and turn red litmus blue. Both conduct electricity in solution because they form ions.

How does the pH scale work?

The pH scale runs from 0 to 14: below 7 is acidic, 7 is neutral, and above 7 is basic. It is logarithmic, so each whole pH unit is a tenfold change in hydrogen ion concentration. A pH of 3 has ten times the hydrogen ion concentration of pH 4 and a hundred times that of pH 5. The lower the pH, the more acidic and the higher the hydrogen ion concentration.

How do I do a titration calculation?

Neutralization is acid plus base gives a salt and water. In a titration you add a titrant of known concentration until an indicator marks the equivalence point. For a 1 to 1 reaction such as HCl with NaOH, the moles of acid equal the moles of base, so $M_a V_a = M_b V_b$ solves for the unknown concentration. For a non-1-to-1 reaction, find the moles of the known solution, apply the mole ratio, then divide by the unknown volume.

VirginiaChemistry

Virginia SOL Chemistry solutions, acids and bases: a complete skills guide to solubility, molarity, the pH scale, neutralization and titration

A deep-dive Virginia SOL Chemistry guide to solutions, acids and bases (CH.5): solutes and solvents, the dissolving process and solubility curves, molarity and dilution, the Arrhenius and Bronsted-Lowry definitions, the pH scale, and neutralization and titration calculations, with worked problems and SOL exam technique.

Generated by Claude Opus 4.816 min readCH.5Updated 2026-06-13

Reviewed by: AI editorial process; not yet individually human-reviewed

Jump to a section

Why solutions, acids and bases go together
Solutions and solubility
Molarity and dilution
Acids, bases and pH
Neutralization and titration
Check your knowledge

Why solutions, acids and bases go together

Most chemistry happens in solution, and acids and bases are the solutions chemists meet most often. Standard CH.5 covers how solutions form, how concentration is measured, and how acids and bases behave and react. These skills lean on the mole and stoichiometry from earlier in the course and feed directly into the titration calculations that the SOL favors. This guide ties together the matching dot-point pages, each with its own practice: solutions, solubility and concentration, molarity and solution stoichiometry, acids, bases and the pH scale, and neutralization and titration.

Solutions and solubility

A solution is a homogeneous mixture of a solute in a solvent, and dissolving follows "like dissolves like" (polar and ionic in water, nonpolar in nonpolar). The rate of dissolving a solid rises with stirring, heating and surface area, while solubility (the maximum dissolved at a temperature) is mainly set by temperature: up for most solids, down for gases. A solution is unsaturated, saturated or supersaturated, and a solubility curve plots grams of solute per $100$ g of water against temperature.

Molarity and dilution

Molarity is moles of solute per liter of solution:

M = \frac{\text{moles of solute}}{\text{liters of solution}}, \qquad \text{moles} = M \times V

Dilution adds solvent without changing the moles, so $M_1 V_1 = M_2 V_2$ . Molarity is the bridge from a measured volume of solution to the moles needed for stoichiometry.

Acids, bases and pH

An Arrhenius acid gives $\text{H}^+$ in water and a base gives $\text{OH}^-$ ; a Bronsted-Lowry acid donates a proton and a base accepts one. Acids are sour and turn blue litmus red; bases are bitter, slippery and turn red litmus blue. The pH scale runs $0$ to $14$ (below $7$ acidic, $7$ neutral, above $7$ basic) and is logarithmic, so each unit is a tenfold change in hydrogen ion concentration.

Neutralization and titration

Neutralization is acid + base $\rightarrow$ salt + water. A titration finds an unknown concentration by adding a titrant of known concentration to the equivalence point, signaled by an indicator. For a $1 : 1$ reaction, $M_a V_a = M_b V_b$ .

A titration calculation

A $25.0$ mL sample of $\text{HCl}$ is neutralized by $50.0$ mL of $0.20$ M $\text{NaOH}$ in a $1 : 1$ reaction. Find the molarity of the acid.

step 1 Confirm the ratio

$\text{HCl} + \text{NaOH} \rightarrow \text{NaCl} + \text{H}_2\text{O}$ is $1 : 1$ , so $M_a V_a = M_b V_b$ applies.

step 2 Rearrange for the unknown

$M_a = \dfrac{M_b V_b}{V_a}$ .

step 3 Substitute

$M_a = \dfrac{(0.20\ \text{M})(50.0\ \text{mL})}{25.0\ \text{mL}} = 0.40$ M.

step 4 Check

A smaller volume of acid neutralized a larger volume of base, so the acid is more concentrated, which $0.40$ M (versus $0.20$ M) confirms.

A solution is a solute dissolved in a solvent, following like dissolves like; the rate of dissolving a solid rises with stirring, heat and surface area, while solubility (the maximum, set by temperature) rises for solids and falls for gases, and a solubility curve plots grams per 100 g of water against temperature. Molarity is moles per liter ( $M = \text{moles}/\text{liters}$ ), and dilution conserves moles ( $M_1 V_1 = M_2 V_2$ ). Arrhenius acids give hydrogen ions and bases give hydroxide ions (Bronsted-Lowry: proton donor and acceptor). The pH scale runs 0 to 14 (below 7 acidic, above 7 basic) and is logarithmic, a tenfold change per unit. Neutralization gives a salt and water, and a 1 to 1 titration uses $M_a V_a = M_b V_b$ to find an unknown concentration.

Check your knowledge

Attempt these under timed conditions, then check the solutions.

Name two ways to increase the rate at which a solid dissolves. (2 marks)
Calculate the molarity of a solution with $0.75$ mol of solute in $3.0$ L of solution. (2 marks)
A $4.0$ M stock solution is diluted to make $2.0$ L of $1.0$ M solution. What volume of stock is needed? (2 marks)
State whether a solution of pH $11$ is acidic, neutral or basic, and name one property of such a solution. (2 marks)
Write the products of the neutralization $\text{H}_2\text{SO}_4 + 2\,\text{NaOH} \rightarrow$ ?. (1 mark)
In a $1 : 1$ titration, $30.0$ mL of acid is neutralized by $15.0$ mL of $0.40$ M base. Find the acid molarity. (2 marks)

Sources & how we know this

2018 Science Standards of Learning - Chemistry — Virginia Department of Education (2018)
Chemistry Curriculum Framework — Virginia Department of Education (2018)