Karnataka Board Class 10 Science — Flashcards for Quick Revision

A: Balanced equation: 2Mg(s) + O₂(g) → 2MgO(s) This is a combination reaction because two reactants (Mg and O₂) combine to form a single product (MgO). It's also exothermic as heat and light are released

A: Iron is more reactive than copper, so it displaces copper from copper sulphate solution. Reaction: Fe(s) + CuSO₄(aq) → FeSO₄(aq) + Cu(s). The brownish coating is copper metal deposited on iron. Blue c

A: Green ferrous sulphate crystals turn reddish-brown and emit SO₂ gas with a burning sulfur smell. Equation: 2FeSO₄(s) → Fe₂O₃(s) + SO₂(g) + SO₃(g) This is a thermal decomposition reaction where one rea

A: Metals are good conductors because their electrons can move freely. You get a shock because your body completes the electrical circuit. Prevention: Use insulated wires (covered with PVC/rubber) and av

A: Aluminum and copper are excellent heat conductors, allowing even cooking. Iron rusts and affects food taste, while lead is toxic. Aluminum is lightweight and doesn't react with most foods. Copper cond

A: Zn + CuSO₄ → ZnSO₄ + Cu. The blue copper sulfate solution turns colorless, and reddish-brown copper metal is deposited. This happens because zinc is more reactive than copper (higher in reactivity ser

A: The blue litmus paper will turn red. Lemon juice contains citric acid, which produces H⁺ ions in solution. Acids always change blue litmus to red, indicating their acidic nature.

A: Baking soda (NaHCO₃) is a mild base that neutralizes excess HCl acid in the stomach. The neutralization reaction: NaHCO₃ + HCl → NaCl + H₂O + CO₂. This reduces acidity and provides relief.

A: Hydrogen gas is evolved with effervescence. Reaction: Zn + 2HCl → ZnCl₂ + H₂↑. The hydrogen gas can be tested by bringing a burning candle near it - it burns with a 'pop' sound.