Mixing two clear liquids results in the formation of a whit solid. Is this a physical or chemical change?

Which real-world scenarios below represent physical and chemical changes? -running a car -exploding fireworks -mixing water and powdered drink mix -combining oil and vinegar to make salad dressing -taking aspirin for a headache -diluting bleach with water-digesting dinner-spreading peanut butter on bread

Can someone me with 1 to 4 plz. fast

In the reaction between a crushed antacid tablet and vinegar what gas is emitted