115) A greenish yellow gas reacts with an alkali metal hydroxide to form a halate, which can be used in fireworks and safety matches. The gas and halate respectively are:

116) The maximum percentage of available chlorine on the basis of CaOCl₂.H₂O formula is:

117) In which of the following pairs, are the two species iso structural?

118) When a white hygroscopic powder X is treated with cold water, a compound Y is formed, which forms a white precipitate with BaCl₂ in acidic medium. Y also gives a white amorphous precipitate with neutral AgNO₃. Compound Y can also be obtained by heating H₃PO₄. X and Y are:

119) A compound A of S, Cl and O has a vapour density of 67.5. It reacts with water to form two acids and reacts with KOH to form two salts B and C. B gives white precipitate with AgNO₃ solution and C gives white precipitate with BaCl₂ solution. Identify A.