Which among the following is a chemical change?

Which among the following is the major constituent of soda lime glass?

Which one among the following is the most appropriate statement with respect to the atomic weight of an element?

Which one among the following transitions of electron of hydrogen atom emits radiation of the shortest wavelength?

 Which one among the following is the correct order of amount of lime (CaO), silica (SiO₂), alumina (Al₂O₃) and ferric oxide (Fe₂O₃) in Portland cement

Which one among the following nitrogen compounds has the least percentage of nitrogen by mass