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:
% comp. H = 2.8%, % comp. Cl = 97.2%
Explanation:
HCl mass = mass of H + mass of Cl
HCL mass = 1.00794 + 35.453 = 36.46094
% comp. of H = 1.007694 / 36.46094 x 100 = around 2.8% (2.76376308455)
% comp. of Cl = 35.453 / 36.46094 x 100 = around 97.2% (97.2355622208)
Answer is: Increased pressure would increase the rate of forming water vapor.
According to Le Chatelier's Principle, the position of equilibrium moves to counteract the change, the position of equilibrium will move so that the concentration of products (water waper) of chemical reaction increase, if:
1) decrease temperature, because this is exothermic reaction (ΔH is negative).
2) increase concentration of reactants (oxygen and hydrogen).
3) increase pressure of the system, so reaction moves to direction where is less molecules.
Answer:
it will send the message through the axon
