NCERT Class 10 Science Textbook made Screen Readable by Raunak Padhi from USA and Dr T K Bansal.

Important Note:

Before going further, let me explain that chemical reactions are written in symbolic form. When it comes to writing the chemical reactions for sighted students, there is no difficulty. However, when we have to present them for blind and visually impaired students, there are difficulties. When we write these equations for blind and visually impaired students, it is required that both the partially sighted students should be able to see these equations by magnifying them, and otherwise, the screen readers should read them the way they should be read. For example, let me take the reaction of iron with water, and write it in different forms:

When writing in the text form:
Fe + O2 → Fe3O4 + H2;
In this form the equation is neither fine visually nor for the screen readers.

When coding it in HTML, we get;
Fe + O₂ → Fe₃O₄ + O₂;
Now it is fine visually, but not for the screen readers.

Writing it using Mathtype notations, we get;
Fe + O_2 → Fe_3O_4 + H_2;
This is understandable using screen readers, but is not fine visually.

Finally let me code it using Mathtype notation, and display it using Mathjacks;

$$Fe + O_2 → Fe_3O_4 + H_2;$$

This form of writing chemical reactions is fine both for screen readers and visually.

It is therefore, in this chapter, most of the chemical reactions are presented in this form.