Give reason Why:
(a) Respiration is consider as exotermic reaction
(b) Curd & sour substance not kept in brass vessel.
(c) DRy HCL gas does change the colour of dry litmus.
(d) P.O.P.should be stored in moisture proof container.
(e) Sodium kept in kerosene.
(f) Ionic compounds have high melting point.
Answers
Answer:
Exothermic reactions release heat or energy.When you or we breath out,breath is warmer.This is happened for respiration reaction of our body.
Carbolydrates present in food are broken down to form glucose.This glucose combines with oxygen in the cells of our body and provides energy.This reaction is known as respiration.hence,respiration is considered as an exothermic reaction.
Curd and sour substances contain acids. Acids react with metals to produce salt and hydrogen gas. So, if such substances are kept in copper container, the acid will react and the container will be corroded.
Colour of the litmus paper is changed by the hydrogen ions. Dry HCl gas does not contain H+ ions. It is only in the aqueous solution that an acid dissociates to give ions. Since in this case, neither HCl is in the aqueous form nor the litmus paper is wet, therefore, the colour of the litmus paper does not change.
Plaster of Paris (POP) should be stored in a moisture-proof container because Plaster of Paris, a powdery mass, absorbs water (moisture) to form a hard solid known as gypsum.
Sodium and Potassium are highly reactive metals and react vigorously with the oxygen, carbon dioxide and moisture present in the air such that it may even cause a fire. To prevent this explosive reaction, Sodium is kept immersed in kerosene because Sodium doesn't react with kerosene.
Ionic compounds have an equal number of positive and negative ions arranged in the three-dimensional lattice due to which they have high melting points.
The strong force of attraction between oppositely charged ions means that ionic compounds have high melting and boiling points.
When dissolved in water ionic compounds form a solution in which ions can move. This means that these solutions can conduct electricity.
Similarly, if ionic compounds are heated up so that they melt the ions can move and molten ionic compounds can also conduct electricity.
The positive and negative ions formed during ionic bonding are held together by enormously strong forces of attraction between the oppositely charged ions. These ionic bonds between the charged particles result in a giant structure of ions. Because the ions are held together tightly in this giant structure it takes a lot of energy to break all the bonds. As a result, ionic compounds have high melting and boiling points.