general characteristics of alkanes

Question 1

physical properties of alkanes

Answer 1

depend upon weak vander waals froces only as theyre non polar,
which mainly depend upon the surface area

Question 2

state of matter of alkane

Answer 2

C1-C4: gas
C5-C17: liquid
C18 onwards: solid

all are odorless and colorless

Question 3

desnity of alkane

Answer 3

increases v slowly w rise in molecular mass nd stops at 0.8 (so all r lighter than water)

Question 4

solubility of alkanes

Answer 4

soluble in non polar insoluble in polar,
liq hydrocarbons themselves are good non-polar solvents

Question 5

boiling points of alkanes

Answer 5

increase w increase in carbon atoms
among branched ones, least branched ones have highest BP

Question 6

melting points of alkanes

Answer 6

alkanes w even no. of carbons have higher bp than next or previous one with odd carbon atoms due to the fact that end carbons of an even carbon chain are on opposite sides

Question 7

chemical properties

Answer 7

pls refer to page 6.8 of op tandon book ch. alkanes

Question 8

substitution reaction of alkanes- halogenation

Answer 8

alkanes treated w halogens(mainly Cl nd Br) in presence of sunlight or UV
hydrogrens r replaced with halogens ONE BY ONE
eg clorination of methane

bond energy for extraction of hydrogen- CH3> 1 DEGREE> 2 DEGREE> 3 DEGREE