Answer:
A. They must be kept separate from moisture and oxygen
Explanation:
Alkali metals refers to a group of chemical elements in the periodic table. It is the common name given to Group 1 elements (excluding hydrogen). They are generally metallic in nature with physical properties like shining lustre, silvery in appearance etc. Alkali metals include lithium, Pottasium, Sodium, Rubidium etc.
One important chemical property of alkali metals is their high reactivity i.e. they tend to react quickly with other substances. For example, alkali metals react vigorously with water to form hydroxides. They also react with oxygen to form oxides. Due to this highly reactive properties, they are kept or stored away from moisture (water) and oxygen (present in air).
Hydrogen Ions exist in acid solutions.
Answer:
Molar mass of unknown solute is 679 g/mol
Explanation:
Let us assume that the solute is a non-electrolyte.
For a solution with non-electrolyte solute remains dissolved in it -
Depression in freezing point of solution, 
where, m is molality of solute in solution and 
is cryogenoscopic constant of solvent.
Here 
If molar mass of unknown solute is M g/mol then-
So, 
so, M = 679 g/mol
a) NH₃ molecules have stronger intermolecular attractions than CH₄ molecules.
Explanation:
Ammonia molecules have stronger intermolecular attractions compared to methane.
Ammonia molecules have london dispersion forces and hydrogen bonds between their molecules.
Methane molecules have only london dispersion forces in their structure.
- hydrogen bonds are very strong attractive forces between molecules in which the hydrogen of a molecule is attracted by a more electronegative atom of another usually oxygen, nitrogen and fluorine.
- London dispersion forces are weak forces of attraction between heteronuclear atoms.
Learn more:
Hydrogen bonds brainly.com/question/10602513
#learnwithBrainly
