Answer:
Formation of intermolecular hydrogen bonding between water molecules and molecules of n-butanol
Explanation:
Low molecular weight alcohols are miscible with water in all proportions. The reason for this is that, when a low molecular weight alcohol is dissolved in water, intermolecular hydrogen bonds are formed between the low molecular weight alcohol and water molecules.
Low molecular weight alcohols such as n-butanol contain the polar -OH group which interacts with water via hydrogen bonding.
Atoms that have lost or gained one or more electrons are called ions.
Answer: 1. C. polar covalent: electrons shared between silicon and sulfur but attracted more to the sulfur
2. B) 
3. B) Fluorine
Explanation:
1. A polar covalent bond is defined as the bond which is formed when there is a difference of electronegativities between the atoms.
Electronegativity difference = electronegativity of sulphur- electronegativity of silicon = 2.5 -1.8 = 0.7
Thus as electronegativity difference is less than 1.7 , the cond is polar covalent and as electronegativity of sulphur is more , the electrons will be more towards sulphur.
2. A molecular compound is usually composed of two or more nonmetal elements. Example:
Ionic compound is formed by the transfer of electrons from metals to non metals. Example:
,
and 
3. For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
Here K is having an oxidation state of +1 and as the compound formed is KZ, the oxidation state of non metallic element Z should be -1. Thus the element Z is flourine which exists as diatomic gas 
In an ionic bond :
=》B. one atom accepts electrons from another.
in this bond an atom ( <em><u>metallic</u></em> ) loses its electrons and another atom ( <em><u>non- metallic</u></em> ) accepts the electrons, and since there isn't the equal positive and negative charges in the atoms, they forms <em><u>cations</u></em> ( +ve charge ) and <em><u>anions </u></em>( -ve charge )
and get stacked or <em><u>attracted</u></em> to each other by strong <em><u>electrostatic force</u></em>.
Answer is: both reactions
are exothermic.
<span>
In exothermic reactions, heat is released and enthalpy of reaction is less than
zero (as it show second chemical reaction).
According to Le Chatelier's principle when the reaction
is exothermic heat is included as a product (as it show first
chemical reaction).</span>