Definitions [3]
Define pOH.
The pOH of a solution can be defined as the negative logarithm to the base 10, of the molar concentration of OH− ions in solution.
pOH = -log10[OH-]
Define pH.
The pH of a solution is defined as the negative logarithm to the base 10, of the concentration of H+ ions in solution in mol dm–3.
pH is expressed mathematically as
pH = -log10 [H+] or pH = -log10 [H3O+]
Definition: pH scale
pH scale is a scale for measuring the hydrogen ion concentration in a solution.
Key Points
Key Points: Physical Properties of Acids
- Taste & Safety: Acids taste sour; mineral acids are corrosive and should never be tasted.
- Physical State: Acids can be solids (e.g., boric acid) or liquids (e.g., HCl, H₂SO₄); some are volatile, others are not.
- Skin Effect: Strong acids cause burns; conc. H₂SO₄ chars skin, HNO₃ turns it yellow, HCl gives amber color.
- Indicators: Acids turn blue litmus red; also change colors of methyl orange and red cabbage extract.
- Conductivity: Acids conduct electricity in aqueous solutions, acting as electrolytes.
Key Points: The pH Scale
- The pH scale (0–14) measures the concentration of H⁺ ions in a solution; values < 7 indicate acids, > 7 indicate bases, and 7 is neutral.
- A universal indicator shows different colours at different pH levels, helping to determine the strength of an acid or base.
- Strong acids/bases produce more H⁺ or OH⁻ ions in solution, while weak acids/bases produce fewer ions at the same concentration.
Important Questions [17]
- Dilute NaOH can be tested with
- Match the following
- When phenolphthalein is added to NaOH, the colour of the solution will become pink
- From Which Plant is Litmus Paper Or Litmus Solution Obtained?
- The Litmus Paper Or the Litmus Solution is Obtained from ________ Plant
- Phenolphthalein is a Synthetic Type of Indicator.
- Choose the Correct Alternative and Rewrite the Following Sentence. Phenolphthalein is ___________ Type of Indicator.
- When _______________ is Passed Through Fresh Lime Water, It Turns Milky.
- Answer the Following Question: What is the Universal Indicator? Does Mg (Oh)2 React with Sodium Hydroxide? If Not, Why?
- Which Substance When Used with Butter Having Butyric Acid Can Cure Acidity?
- A Person Has Sour Taste in the Mouth and a Burning Sensation of the Stomach.
- Lime water turns milky when ______ gas is passed through it.
- Write Two Applications of Sodium Bicarbonate (Baking Soda).
- Write the Chemical Name of Bleaching Powder and Write Its Properties.
- Give the Molecular Formula of Bleaching Powder.
- Name the product obtained when Plaster of Paris is mixed with water. State the use of the product. Give two uses of POP.
- Sodium Or Potassium Salt of Higher Fatty Acid is Termed
Concepts [9]
- Properties of Acids > Physical Properties
- The pH Scale
- Acids, Bases and Their Reactivity
- Acid or a Base in a Water Solution
- Preparation and Uses of Baking Soda
- Preparation and Uses of Bleaching Powder
- Preparation and Uses of Washing Soda
- Preparation and Uses of Plaster of Paris
- Chemicals from Common Salt - Soap as a Salt
