What are indicators? How methyl orange and phenolphthalein changes their colour in acidic and basic solutions? How litmus paper changes its colour in different solutions?

See the answer below

Explanation:

In chemistry, indicators are substances that are capable of changing colors with respect to the pH. Each indicator has its characteristic color in acidic pH and another characteristic color in alkaline pH.

Methyl orange indicator appears red in acidic solution and yellow in basic solutions. Phenolphthalein is usually colorless in acidic solutions and appears pink in basic solutions. A red litmus paper will turn blue in alkaline solutions while a blue litmus paper will turn red in acidic solutions.

in scientific notation, the value of the  speed of light in a vacuum

  will be written as 2.995 * 10^8. when this value is represented in the form of

  a * 10^b, then, a = 2.995 and b = 8.

the value of the speed of light in a vacuum given above can also be rounded up to approximately 300000000. in this case, the scientific notation will be written as 3 *10^8.

c, liquids evaporate, creating a gas