Which of the following is the softest?

Oxides commonly occur in metals?

Used in removing permanent hardness of water?

On heating copper powder in air, a layer of copper oxide accumulates on its surface. What is the color of this layer?

Is gas given with oxygen to patients for diagnosis of breathing problem?

Which of the following properties does not show metals?

Ant stings occur in?

Herbs- The decomposition of vegetables into compost is an example of which reaction?