Answer:
Explanation:
All three lighter boron trihalides, BX3 (X = F, Cl, Br), form stable adducts with common Lewis bases. Their relative Lewis acidities can be evaluated in terms of the relative exothermicities of the adduct-forming reaction. Such measurements have revealed the following sequence for the Lewis acidity: BF3 < BCl3 < BBr3 (in other words, BBr3 is the strongest Lewis acid).
This trend is commonly attributed to the degree of π-bonding in the planar boron trihalide that would be lost upon pyramidalization (the conversion of the trigonal planar geometry to a tetrahedral one) of the BX3 molecule, which follows this trend: BF3 > BCl3 > BBr3 (that is, BBr3 is the most easily pyramidalized). The criteria for evaluating the relative strength of π-bonding are not clear, however. One suggestion is that the F atom is small compared to the larger Cl and Br atoms, and the lone pair electron in the 2pzorbital of F is readily and easily donated, and overlaps with the empty 2pz orbital of boron. As a result, the [latex]\pi[/latex] donation of F is greater than that of Cl or Br. In an alternative explanation, the low Lewis acidity for BF3 is attributed to the relative weakness of the bond in the adducts F3B-L.
Answer:
Polar Jet stream
Explanation:
Polar Jet stream is also called the polar front jet or mid latitude jet steam, it is a very powerful belt of the upper level winds which sits above the polar front. It is the strongest wind in the tropopause, it's movement is towards the westerly direction of the mid latitude.
Answer:

Explanation:
1. Write the skeleton equation for the half-reaction
NO₃⁻ ⟶ N₂O
2. Balance all atoms other than H and O
2NO₃⁻ ⟶ N₂O
3. Balance O by adding H₂O molecules to the deficient side.
2NO₃⁻ ⟶ N₂O + 5H₂O
4. Balance H by adding H⁺ ions to the deficient side.
2NO₃⁻ + 10H⁺ ⟶ N₂O + 5H₂O
5. Balance charge by adding electrons to the deficient side.
2NO₃⁻ + 10H⁺ + 8e⁻ ⟶ N₂O + 5H₂O
The amount of charge required to reduce 2 mol of NO₃⁻ is 8 F

Potassium is placed where it is based on its properties and it's reactivity. It's also placed there based on it's atomic number.
Explanation:
According to the law of conservation of mass, mass can neither be created nor destroyed but it can simply be transformed from one form to another.
For example, 
Mass of Na = 23 g/mol
Mass of Cl = 35.5 g/mol
Sum of mass of reactants = mass of Na + mass of Cl
= 23 + 35.5 g/mol
= 58.5 g/mol
Mass of product formed is as follows.
Mass of NaCl = mass of Na + mass of Cl
= (23 g/mol + 35.5) g/mol
= 58.5 g/mol
As mass reacted is equal to the amount of mass formed. This shows that mass is conserved.
As a result, law of conservation of mass is obeyed.