ALKANES

Question 1

other name for alkanes

Answer 1

parrafins

Question 2

the reaction alkanes undergo

Answer 2

free radical subst rxn

Question 3

what are the steps of FRS rxn

Answer 3

1- inititaion
2- propagation
3- termination

Question 4

define inititaion

Answer 4

Cl radicals formed

Question 5

define propagation

Answer 5

ch3cl radical formed, Hcl formed

Question 6

temination

Answer 6

1- cl cl radicals react and terminate the chain
2- ch3cl ch3cl radicals terminate
3- ch3cl and cl radicals combine and terminate

Question 7

2 types of cracking, definition of cracking

Answer 7

thermal and catalytic, long chain hydrocarbons converted to short chain (alkenes) and useful HCs

Question 8

thermal cracking

Answer 8

1- high temp high press, 750 C temp

2-cracks upto 8th carbon atom

Question 9

catalytic cracking

Answer 9

1- high temp catalyst
2- takes place in presence of zeolites
3-cracking of more than 8 C atoms

Question 10

uses of cracking

Answer 10

• to meet supply and demand
• ethene production
• get Hydrogen for ammonia production

Question 11

reforming

Answer 11

long chain hydrocarbons converted to branched chain and cyclic HCs

Question 12

reforming condt

Answer 12

500 C temp, 40 atm press, Al2O3 catalyst

Question 13

another rxn for alkanes

Answer 13

combustion

Question 14

combustion 2 types

Answer 14

in excess o2, producing co2 and h20

in limited o2, producing co and h20 and carbon soot

Question 15

formula for combustion

Answer 15

CxHy + x+y/4O2 —-> xCO2 + y/2 H2O

X= no. of C atoms
Y= no. of H atoms