Expected:
sp³ in all three molecules.
<h3>Explanation</h3>
The hybridization of the central atom is related to the number of electron domains around that atom.
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What is an electron domain?
- An atom bonded to the central atom counts as one electron domain. That atom counts as one electron domain regardless of the bond order. One single bond counts as one electron domain. One double bond counts as one electron domain. One triple bond counts as one electron domain.
- A lone pair of electrons count as one electron domain.
How many electron domains in BH₄⁻, CH₄, and NH₄⁺?
- BH₄⁻: Four H atoms are bonded to the central B atom. That ensures an octet for the central B atom. No lone pairs are needed. Four electron domains from the four bonded atoms. sp³ hybridization.
- CH₄: Four electrons domains with four H atoms and no lone pair. sp³ hybridization.
- NH₄⁺: Four electrons with four H atoms and no lone pair. sp³ hybridization.
<span>There are more than 550 active
volcanoes in the world, almost all of which are located at convergent
tectonic plate boundaries. This includes all of the volcanoes in the
Pacific Ring of Fire, such as Japan's Mount Fuji, as well as Mount Saint
Helens, Popocafepetl in Mexico and Azul in the Andes Range.</span>

As depth increases, the density of the layers decreases.
Salutations!
<span>In a laboratory experiment, John uses a mesh to separate soil particles from water. Which technique of separation is he using?
The technique that John is using is the filtration technique. Filtration is a technique to separate the solid which is insoluble from the liquid. For instance: Sand and water, sand is insoluble, thus it stays in the filter paper, while the water proceeds through the filter paper.
Hope I helped :D</span>