Question

ans this and get 200 thnx tommorow​

Answer 1

Answer:

(a) Magnesium ribbon must be cleaned before burning in air so that the layer of magnesium oxide (which is formed due to reaction of magnesium with air) can be removed in order to get the desired chemical reaction.

(b)(i) The solution of the substance used for whitewashing is calcium oxide also called quicklime with chemical formula CaO.

(ii)Quicklime is used for whitewashing as it produces calcium hydroxide (CaOH) when it reacts with water (H2O) and absorbs carbon dioxide (CO2) from the environment, as a result, it produces calcium carbonate (CaCO3) which creates a hard coating on the walls.

It forms slac.ked lime or calcium hydroxide when the quick lime reacts with water

CaO (s) + H2O (l) → Ca(OH)2(aq).

Answer 2

Answer:

1. Answer: Magnesium ribbon must be cleaned before burning in air so that the layer of magnesium oxide (which is formed due to reaction of magnesium with air) can be removed in order to get the desired chemical reaction.
2. Answer: The chemical substance X used for whitewashing is Calcium oxide, also known as quicklime or burnt lime or lime. Calcium oxide is an alkaline earth flux with the chemical formula CaO.
3. Name the substance 'X' and write its formula. Answer: The chemical substance X used for whitewashing is Calcium oxide, also known as quicklime or burnt lime or lime. Calcium oxide is an alkaline earth flux with the chemical formula CaO.
4. (i) Substance X is Calcium Oxide whose solution we use in water which is used for white washing. The formula of substance X is Cao. (ii) Calcium oxide reacts vigorously with water to produce slaked lime (calcium hydroxide) releasing a large amount of heat.