Answer:
C. AlCl3 is a covalent compound.
Explanation:
It is formed by mutual sharing of electrons between two atoms each contributing equal number of electrons to the electron pair.
<u>Answer:</u> The spacing between the crystal planes is 
<u>Explanation:</u>
To calculate the spacing between the crystal planes, we use the equation given by Bragg, which is:
where,
n = order of diffraction = 2
= wavelength of the light = 
(Conversion factor: 
)
d = spacing between the crystal planes = ?
= angle of diffraction = 22.20°
Putting values in above equation, we get:
Hence, the spacing between the crystal planes is
Answer is: an instant ice pack becoming cold, splitting a gas molecule and baking bread.
<span>Endothermic reaction
is chemical reaction that absorbs more energy than it releases.
</span>In ice pack, <span>reaction absorbs heat from the surroundings (endothermic reaction), lowering the surrounding temperature.
For splitting molecule and baking bread we must add energy to break bonds between atoms.</span>
