The salt which is least likely to be found in minerals is

Which of the following minerals of aluminum does not contain oxygen?

The region in which main metals are found in the Earth is called:

Among the following ores: Bauxite,Siderite,Cuprite,Calamine,Haematite,Kaolinite,Malachite,Magnetite,Sphalerite,Limonite,Cryolite,the number of principal ores of iron is $......$

Which element is found in free state?

Which of the following is not an ore of lead?