What is the catalyst used in contact process in the conversion of Sulphur dioxide to Sulphur trioxide?

Which of the following is a suitable test to identify presence of chlorine atoms or ions?

What is the electron gain enthalpy for noble gases?

From which type of phosphorus is alpha -black phosphorus formed?

Which of the following is true about sulphuric acid?

What is the color of chlorine?

What is the temperature at which orthophosphoric acid forms pyrophosphoric acid?

How many stages is the ‘salt cake’ method performed in?