These are the questions

3) 1

4) 0.2

5) 2

6) 1

7) 0.2

Explanation:

3)

The molarity of a substance is defined as the number of moles of the substance divided by how many liters the solution is. NaOH has a molar mass of about 40 grams, meaning that 10 grams of it would be 0.25 moles. 0.25/0.25= a molarity of 1.

4)

CO2 has a molar mass of just about 44 grams, meaning that 44 grams of it would be about a mole. 5000mL of solution is 5 liters, meaning that the molarity of this solution would be 1/5=0.2.

5)

HF has a molar mass of about 20, meaning that 20 grams of it is about a mole. 1/0.5=2M.

6)

Calcium flouride has a molar mass of about 78 grams, meaning that 156 grams is about two moles. 2000mL is 2 liters, meaning that this has a molarity of 2/2=1.

7)

Glucose has a molar mass of about 180 grams, meaning that 360 grams of it would be about 2 moles. 2/10=0.2.

Hope this helps!

the answer is barium and copper bromide

hydrocarbons are organic compounds that contain only hydrogens and carbons. they can be saturated (those which contain only carbon-carbon single bonds) or unsaturated (those which contain carbon-carbon double or triple bonds) in nature. hydrocarbons can undergo several reactions like substitution, elimination etc.  

on substituting one or more hydrogen atoms in hydrocarbon it results in the formation of haloalkane. as the halogen atoms are large compared to the carbon and hydrogen atoms, due to which the molecular weight increases and the bond become polar because of presence electronegative halogen atom and results in the increase in boiling point of the haloalkane.

thus, the correct option is (b) that is the boiling point of the new compound increases on substituting a hydrogen atom with a halogen in a hydrocarbon.