Answer: According to the law of faunal succession, the fossils that are found at the bottom layer are considered to be the oldest, whereas the fossils that are present on the top layer is the youngest.
From the given question, the sable antelope is the youngest, and blue antelope is the oldest. This could suggest that the blue antelopes have undergone evolution and with time, they transformed into the horse, which were found to be present in the middle layer as an evidence. And this animal has further undergone evolution and formed the sable antelopes.
Answer:
Lithium
Explanation:
Alkali metals are group of metals which are present in first group of periodic table. As we know atomic number is equal to number of protons contained by a particular element. Therefore, the alkali metals along with there number of protons are listed below;
Alkali Metal Number of Protons
Lithium 3
Sodium 11
Potassium 19
Rubidium 37
Cesium 55
Francium 87
Hence, it is cleared from above table that Lithium is having fewer protons than 10.
Answer:
pH of the final solution = 3.8
Explanation:
Concentration of NaF = 
molar
= 0.3 molar
NaF → Na⁺ + F⁻
HF ⇆ H⁺ + F⁻
- NaF is strong electrolyte so completely ionized but HF weak acid not completely ionized.
- Since F⁻ is common ion here
according to common ion effect dissociation of weak acid decreases.
Ka = ![\frac{[H]^{+}[F]^{-} }{[HF]}](https://tex.z-dn.net/?f=%5Cfrac%7B%5BH%5D%5E%7B%2B%7D%5BF%5D%5E%7B-%7D%20%20%7D%7B%5BHF%5D%7D)
⇒ [H⁺] = ![\frac{K_{a} [HF]}{[F]^{-} }](https://tex.z-dn.net/?f=%5Cfrac%7BK_%7Ba%7D%20%5BHF%5D%7D%7B%5BF%5D%5E%7B-%7D%20%7D)
...............(1)
{Ka of HF = 3.5 x 10⁻⁴} & Concentration of HF = 30 x 4 x 10⁻³ = 0.12 molar
from equation 1
⇒ [H⁺] = 
[Concentration of F⁻ ≡ Concentration of NaF]
⇒ [H⁺] = 0.00014
⇒pH = - log 0.00014 = 3.85
