The function of hydrochloric acid is to melt the food
Reaction of Cu(NO₃)₂ with each salt is as follow,
1) with KNO₃;
Cu(NO₃)₂ + KNO₃ → Cu(NO₃)₂ + KNO₃
Both salt products are water soluble.
2) With CuSO₄;
Cu(NO₃)₂ + CuSO₄ → CuSO₄ + Cu(NO₃)₂
Again both Salt products are water soluble.
3) With K₂SO₄;
Cu(NO₃)₂ + K₂SO₄ → CuSO₄ + 2 KNO₃
Again both salt products are water soluble.
4) With K₂S;
Cu(NO₃)₂ + K₂S → CuS + 2 KNO₃
In this case CuS is water insoluble, hence precipitates out.
Result:
Option-4 is the correct answer.
The answer is true, catalysts increase rates by lowering the activation energy of a reaction. Catalysts lower the reaction energy and so the reaction occurs faster. Enzymes perform the role of biological catalysts. Most metabolic pathways of the body are controlled by enzymes. Enzymes by classification are proteins. <span />
