Question

Question 9 0.2 pts Which one of the following substances has London dispersion forces as its only intermolecular force? (No hydrogen bonding, no dipole-dipole forces.) о сезон NH3 H2S O CH4 Question 10 0.2 pts True or False. Most of the substances used in this investigation are extremely volatile (easily evaporate) and should be used with care in a fume hood. True O False Question 11 O pts True or False. To avoid fainting or feeling light-headed in the lab room, drink water and/or eat something before lab. True False

Answer 1

9. Hydrogen bonding is the strongest inter-molecular force which occurs when hydrogen is directly connected to most electronegative elements of periodic table (nitrogen,oxygen and flourine)

dipole dipole force of attraction is a type of van der waal force in which polar molecules(molecules which are polar due to electro-negativity difference in elements within the compound) are attracted to each other due to their difference in polarity

London dispersive forces is th weakest force of attraction in which non-polar molecules attract each other due to the position of electrons present in molecules

a) CH₃OH - in this compound,oxygen is connected to hydrogen,so hydrogen bonding takes place,so it is incorrect

b) NH₃ - in this compound, nitrogen is connected to hydrogen,so hydrogen bonding takes place, it is also incorrect

c) H₂S - it is a polar molecule,due to electronegativity difference between hydrogen and sulfur,dipole-dipole force occurs,so it is incorrect

d)CH₄ - inspite of electronegativity difference,shape of CH₄ makes it non polar as polarity gets cancelled out,so only london force occurs in this compound,therefore it is the correct option

10. True,Fume hood is a machine which captures dust,volatile and highly toxic material and makes lab safe,so volatile substance should be used in fume hood

11.True,water and food regulates the blood circulation in body due to which tendency of feeling unconscious reduces,so eat and drink before going to lab. DO NOT EAT OR DRINK ANYTHING IN LAB