The number of formula units of calcium fluoride, CaF₂ present in 146.4 g of CaF₂ (the molar mass of CaF₂is 78.08 g/mol) is

• 1.129 $\times {10}^{24} {\mathrm{CaF}}_2$

• 1.146 $\times {10}^{24} {\mathrm{CaF}}_2$

• 7.808 $\times {10}^{24} {\mathrm{CaF}}_2$

• $1.877 \times {10}^{24} {\mathrm{CaF}}_2$

The amount of energy released when 20 mL of 0.5 M NaOH are mixed with 100 mL of 0.1 M HCl is x kJ. The heat of neutralisation is (in kJ mol^-1).

• -100x

• -50x

• +100x

• +50x

293.

Two organic compounds (A) and (B) both containing only carbon and hydrogen, on quantitative analysis gave the same percentage composition by weight

$\mathrm{C}=\left(\frac{12}{13}\right) \times 100 \% \mathrm{H}= \left(\frac{1}{13}\right) \times 100\%$

A decolourises bromine water but B does not. A and B respectively are

• C₂H₂ and C₆H₆

• C₆H₆ and C₂H₂

• C₂H₄ and C₂H₆

• C₂H₂ and C₂H₆

How many grams of dibasic acid (mol. wt. 200) should be present in 100 mL of the aqueous solution to give 0.1 N?

• 10 g

• 20 g

• 2 g

• 1 g

At STP, a container has 1 mole of Ar, 2 moles of CO₂, 3 moles of O₂, and 4 moles of N₂. Without changing the total pressure if one mole of O₂ is removed, the partial pressure of O₂ is

• changed by about 16%

• halved

• changed by 26%

• unchanged

In a compound C, H and N are present in 9 : 1 : 3.5 by weight. If molecular weight of the compound is 108, then the molecular formula of the compound is

• C₂H₆N₂

• C₃H₄N

• C₆H₈N₂

• C₉H₁₂N₃

What amount of bromine will be required to convert 2 g of phenol into 2, 4, 6-tribromo phenol?

• 4.00

• 6.00

• 10.22

• 20.44

What is the amount of urea dissolved per litre, if aqueous solution is isotonic with 10% cane sugar solution (mol. wt. of urea = 60) ?

• 200 g/L

• 19.2 g/L

• 17.54 g/L

• 16.7 g/L

The volume of 2 N H₂SO₄ solution is 0.1 dm³. The volume of its decinormal solution (in dm³) will be

• 0.1

• 0.2

• 2

• 1.7

The percentage (by weight) of sodium hydroxide in a 1.25 molal NaOH solution is

• 4.76%

• 1.25%

• 5%

• 40%