Answer: The bond between boron and hydrogen in boron trihydride is covalent bond.
Explanation:
The type of bonding between the atoms forming a compound is determined by using the electronegativity difference between the atoms. According to the pauling's electronegativity rule:
- If
, then the bond is non-polar. - If
, then the bond will be covalent. - If
, then the bond will be ionic.
We are given:
Electronegativity for boron = 2.0
Electronegativity for hydrogen = 2.1
As, 
is less than 1.7 and not equal to 0. Hence, the bond between boron and hydrogen is covalent bond.
Answer:
a. 2,9x10⁻⁴ M HCl
Explanation:
A solution is considered acidic when its concentration of H⁺ is higher than 1x10⁻⁷. The higher concentration of H⁺ will be the most acidic solution.
a. 2,9x10⁻⁴ M HCl. In water, this solution dissolves as H⁺ and Cl⁻. That means concentration of H⁺ is 2,9x10⁻⁴ M.
b. 4,5x10⁻⁵M HNO₃. In the same way, concentration of H⁺ is 4,5x10⁻⁵M.
c. 1,0x10⁻⁷M NaCl. As this solution doesn't produce H⁺, the solution is not acidic
d. 1,5x10⁻²M KOH. This solution produce OH⁻. That means the solution is basic nor acidic.
Thus, the solution considered the most acidic is a. 2,9x10⁻⁴ M HCl, because has the higher concentration of H⁺.
I hope it helps!
