Can Alt key alone be used as a modifier in web apps? Eg alt + >, alt + k, alt + a

You Can! But if you want to know the real paradigm of the user, shortcuts with Alt is not very common and not easily predictable from the point of view of typical users.

1. What is the use of Alt K?
2. Which keys are called as modifiers in a keyboard?
3. Which is not a modifier key?
4. What can I use instead of Alt?

What is the use of Alt K?

Alt+K is a keyboard shortcut often used to open the Transitions tab in the Ribbon.

Which keys are called as modifiers in a keyboard?

Ctrl, Alt, and Shift are the modifier keys on a typical modern keyboard.

Which is not a modifier key?

The correct answer is Tab. Tab key is not a modifier key in an IBM compatible computer. A modifier key is a key on a computer's keyboard used in conjunction with another key or the one that temporarily modifies the normal action of another key when pressed simultaneously.

What can I use instead of Alt?

The following image of a keyboard shows the location of the Alt keys, which are highlighted in blue. Apple computer keyboards use the option key instead of the Alt key.