Organic Chemistry — Chemistry STD 10 — Question

Name the purest form of iron.

Give reason for the following:
In the electrolysis of acidified water, dilute sulphuric acid is preferred to dilute nitric acid for acidification.

Name of the first member of alkyne series.

State what would you observe when a piece of moist red litmus paper is placed in a gas jar of ammonia.

The following table shows the tests a student performed on four different aqueous solutions which are X,Y,Z and W. Based on the observations provided, Identify the cation present

Chemical Test	Observation	Conclusion
To Solution X, ammonium hydroxide is added in minium quantity first and then in excess	A dirty white precipitate is formed which dissolves in excess to form a clear solution	(i)
To Solution Y, ammonium hydroxide is added in minimum quantity first and then in excess	A pale blue precipitate is formed which dissolves in excess to form a clear inky blue solution	(ii)
To solution W, A small quantity of sodium hydroxide solution is added and then in excess	A white precipitate is formed which remains insoluble	(iii)
To a salt Z, calcium hydroxide solution is added and then heated	A pungent smelling gas turning moist red litmus paper blue is obtained	(iv)

Write an equation for the reactions of hydrochloric acid on manganese (IV) oxide

Give balanced reactions for the following conversion:
Ammonia solution to an amphoteric hydroxide.

What should be added to Increase the pH value .