Question

a metal salt MX when expose to light splits upto form metal M and gas X2, metal M is used in making aurnaments whereas gas X2 is used in making bleaching powder the salt MX the salt MX is itself use in black and white photography

1 what do you think metal M is ?

2 what could be the gas X2?

3 name the metal salt MX?

4 what type of chemical equation takes place when salt MX expose to light . write equation

Answer 1

1 The metal M is silver 
2 the gas X2 could be Cl2 since its used to make bleaching powder 
3 metal salt MX is silver chloride hence its ionic bond maybe halide salt
4 reaction is photo decomposition 
      i.e silver chloride -------------> silver + cholride gas [in presence of light]