Which of the following leaves no residue on heating ?

Which of the following give no residue on heating?

Which of the following give no residue on heating?

Which of the following leaves a black residue on the addition of NH_(3) ?

Which of the following leaves a black residue on the addition of NH_(3) ?

Which one of the following is a residual earning ?

On strongly heating, a blue salt leaves a black residue. Which of the following cations can be present in the salt?

On strongly heating, a blue salt leaves a black residue. Which of the following cations can be present in the salt?