Introduction

Hydrogen exists in the elemental form as the gas H2.

Compounds of hydrogen and most other elements in the periodic table exist. In most cases these can be produced by direct reaction of H2 with the second element under appropriate conditions.

Compounds containing two elements are referred to as binary compounds.  The binary compounds of hydrogen are represented by EHn where n depends on the location of element E in the periodic table.
 
In the scheme associated with this module you will learn how to deduce n in the formula of these compounds for several different elements.

The acid-base properties of EHn also depend on the position of E in the periodic table.
 
In the second section of this module, the trends in acidity and basicity of these compounds and the corresponding En– ions will be explored.