Answers Assignment 5 - Chemical Reactions and Equations | Class 10th

Answers

Assignment – 5

Chemical Reactions and Equations

Ans 21. Green coloured ferrous sulphate crystals FeSO₄.7H₂O looses and also decomposes to form brown oxide of Iron Fe₂O₃ with evolution of SO₂ and SO₃.

Ans 22. In a photochemical reaction AgCl decompose to Ag(s) grey coloured mass.

Ans 23. Silver or gold are least electropositive metals and hence do not react easily when exposed to air, water or light.

Ans 24.  Only strong metal can replace weak metal from salt solution but not vice versa.

Ans 25. When Iron nails are exposed to air and water, it forms brown colour on nails at least in 3-4 days.

Ans 26. When lime water stick on walls react with CO₂ of air to forms a layer of CaCO₃ which is white in colour. 

Ans 27. Both burning of Fuel and food are oxidation reaction, in burning of fuel CO₂ and heat is released and in burning of Food, A.T.P. energy and CO₂ are formed.

Ans 28. Rusting is avoided in stainless steel because it is an alloy.

Ans 29. In cracker explosion, on burning fuel or material like charcoal, sulphur or potassium chloride react with oxygen in oxidation reaction. 

Ans 30. Iron is coated with zinc to protect it from direct contact of air and moisture to avoid rusting.

Ans 31. Platinum is noble metal and has place right to hydrogen, hence do not react with dilute sulphuric acid.

Ans 32. In the reaction of BaCl₂ (aq) with NaCl(aq), BaSO₄ (s) precipitate is formed which is heavy and insoluble in water

Ans 33. Yes, silver nitrate solution reacts on heating with copper metal powder to form silver metal.

Ans 34. Magnesium plate provides electrons and avoid oxidation of Iron metal to protect heavy machines from rusting.