b. Polar covalent bonds. The polar N-H bonds hold the NH3 molecules together. They are <em>intramolecular forces</em> of attraction <em>within a molecule</em>.
All the other options are <em>wrong</em>. They are <em>intermolecular forces</em> — the attractive forces <em>between different molecules</em>.
Answer: Option (d) is the correct answer.
Explanation:
According to law of conservation of mass, the mass of reactants equal to the mass of products.
Therefore, when liquid 1 and liquid 2 reacts then their respective mass will be equal to the mass of products.
In a chemical equation, reactants are written of the left hand side whereas products are written on the right hand side.
Hence, we can conclude that following equation supports law of conservation of mass.
A Diels-Alder reaction is an addition reaction involving a substituted alkane and a diene forming a cyclic aromatic compound. The resulting cycloalkene will be disubstituted with only one double bond in the ring. The 2 pi bonds from the diene will be replaced by 2 sigma bonds.
Valance electrons are the extra electrons on the outermost orbital, that hasn't been filled yet. For example, Lithium would have one valence electron, on the 2s orbital, because that is an extra electron floating around that 2s orbital, that can be shared with others, since each element's goal is to have no valence electrons. If an orbital is filled, it therefore has no valence electrons, because valence electrons are only extra electrons, if that makes any sense.
There are many groups of the periodic table. These groups categorize electrons by the amount of valence electrons they have. The group on the far left, the alkali metals, all have one valence electrons. The alkali metals include Lithium, Sodium, and other elements, so therefore give away that one electron easily, because if they give it away they won't have any valence electrons. (This is why you often see salt, sodium chloride, because sodium gives away its one valence electron to chloride, who needs one electron to have no valence electrons.) One other notable group is the noble gases, on the far right of the periodic table. These elements have no valence electrons, so therefore won't bond easily with other elements.
Hope this helped!