Hydrogen is the most abundant element in the universe, but in free state it is almost not found in earth's atmosphere.
Do you expect carbohydrides of the type `C_nH_(2n+2)` to act as Lewis acid or base? Why?

Hydrogen is the most abundant element in the universe. But in free state it is almost not found in earth's atmosphere. Suggest any three method for the preparation of H_2 , gas.

Hydrogen is the most abundant element in the universe, but in free state it is almost not found in earth's atmosphere. suggest any three methods for the preparation of H_2 gas by selecting suitable substance given below.

Which of the following statements are true? i) Elements which are least reactive occur in free state or native state ii) Earthly or undesired materials present along with ore are called gangue iii) Among metals, aluminium is the most abundant in the earth crust iv) All ores are minerals but all minerals are not ores v) Gemstone "Ruby" is the impure form of Al_2O_3 containing impurity : Co vi) The set of d-block elements Cu, Ag, Au mostly occur as sulphide ore

If an element is in its highest possibel oxidation state in a compound, it can act as an oxidising agent. If an element is in its lowest possible oxidation state in a compound, if can act as reducing agent. If an element is in the intermediate oxidation state in a compound, it can serve as both oxidising and reducing agent. Based on the above three guidelines, classify the following compounds into three categories and post them in the table given below. KMnO_4 , H_2O_2 , H_2C_2O_4 , FeSO_4 , HCIO_4 , SO_2 , Na_2S_2O_3 , K_2Cr_2O_7