Answer: b). The B−A−B angles between neighboring B atoms are 90∘.
Explanation: The square planar geometry is the geometry in which the four groups are connected through an angle of 90∘ and all 5 atoms are in one plane.
It is not necessary for the molecule to have two non bonding pair of electrons on atom A but if it does have , then its parent geometry will be distorted octahedral. And if it doesn't have this non bonding pair of electrons then the geometry would be the square planar.
Thus the molecule has four electron domains about the central atom A if the parent geometry is square planar otherwise it would have 8 electron domain in distorted octahedral geometry.
Answer: observe the rate of the reaction and then observe it again with the catalyst included.
Explanation:
Rate of the reaction is determined by how fast reactants change into products.
The reactants must possess a minimum amount of energy called as activation energy to cross the energy barrier and convert to products.
A catalyst is a substance which when added to a chemical reaction, increases the rate of a reaction by taking the reaction through a different path which involves lower activation energy and thus more molecules can cross the energy barrier and convert to products.
The catalyst thus increases the rate of reaction.
Answer:
Explanation:
To find the density of nitrogen gas at STP which is standard temperature and pressure, certain parameters must be known.
The mass of the gas must be given or its volume.
Density of a substance is the mass per unit area;
Volume of gas at STP = number of moles x 22.4
Using the volume obtained here,
Density = 
Then we can find the density.
The mass is very important.
Answer:
Again please specify your question, you still haven't indicated what you want to be solved.
by formula units I assume you mean atoms?
I'll edit my answer accordingly if you could specify down in the comments.