Question

A chemist mixes lead (ii) nitrate and potassium iodide solutions (both of which are clear liquids) yellow precipitate appears in the final solution. the remaining liquid is an ionic solution. solid precipitates containing lead are always yellow

Answer 1

Chemical reaction: Pb(NO₃)₂(aq) + 2KI(aq) → PbI₂(s) + 2KNO₃(aq).
aq(aqueous) means dissolved in water.
s(solid) means that salt (in this reaction PbI₂) not dissolved in water.
This chemical reaction is double displacement reaction - cations (Pb²⁺ and K⁺) and anions (NO₃⁻ and I⁻) of the two reactants switch places and form two new compounds.