<u>Answer:</u>
For 1: The correct answer is option D.
For 2: The correct answer is option A.
<u>Explanation:</u>
There are two types of molecules which can be categorized on the basis of electronegativity difference:
Polar molecules: In these type of molecules, the two atoms combining must be different so that a dipole can be created and for that the electronegativity of two atoms combining must not be same. The negative dipole of charge is created on the electronegative atom and positive dipole or charge is created on the electropositive atom.
Hence, the correct answer is option D.
Non-polar molecules are defined as the molecules which do not have any dipole and is formed when two atoms of same element combine together which have the same electronegativity. The electronegativity difference of these molecules is 0.
Hence, the correct answer is A.
Answer:
Sodium sulfide is the chemical compound with the formula Na 2 S, or more commonly its hydrate Na 2 S·9H 2 O. Both are colorless water-soluble salts that give strongly alkaline solutions. When exposed to moist air, Na 2 S and its hydrates emit hydrogen sulfide , which smells like rotten eggs.
I'm not sure if it's right but it's a guess because of the 2Na.
Answer:

Explanation:
Hello,
In this case, for us to compute the final volume we apply the Boyle's law that analyzes the pressure-volume temperature as an inversely proportional relationship:

So we solve for
by firstly computing the initial pressure:


Finally, we can compute the work by using the following formula:

Best regards.
You need to be able to draw dot-and-cross diagrams to show the ions in some common ionic compounds.