The following derivatives of benzoic acid: 4-nitrobenzoic acid and 4-chlorobenzoic acid? are they more acidic or less acidic than benzoic acid? and why?

4-nitrobenzoic acid is more acidic than benzoic acid.

Explanation:

After releasing H+, ion benzoate ion is formed (shown in attachment). Benzoate ion is a anoinic species. Acidity of benzoic cid depends upon the stability of benzoate ion.

More will be the stability of benzoate ion, greater will be the acidity.

Benzoate ion will be stabilised by the electronwithdrawing group and destabilised by electrondonating group. This is because electron withdrawing group tends to decrease the electron density on the compound.

In 4-nitrobenzoic acid, nitro group attached to the para position of benzene. -NO2 is an electron withdrawing group and withdraws electrons through -I and -R group and thus stabilises benzoate ion.

4-chlorobenzoic acid, -Cl is bonded to para position of benzene ring. -Cl exterts +R and -I. -Cl through +R effect increases electron density on the benzene ring and through -I decreases electron density. but +R effect is more pronounced. so 4-benzoate ion is more destablised as compared to benzoate ion. Hence, it is a weaker acid than benzoic acid

Therefore, 4-nitrobenzoic acid is more acidic than benzoic acid.

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.

the answer is a and have a great day