Which of The following has a maximum number of molecules?

1. 7g N₂ 

2. 2g H₂ 

3. 16g NO₂ 

4. 16g O₂ 

The number of moles of KMnO₄ reduced by one mole of KI in an alkaline medium is- 

1. One fifth 

2. Five

3. One

4. Two

The number of moles of oxygen in 1L of air containing 21% oxygen by volume, under standard conditions, is 

1. 0.0093 mole

2. 2.10 moles

3. 0.186 mole

4. 0.21 mole

What volume of  oxygen gas (O₂) measured at $0°\mathrm{C}$ and 1 atm, is needed to burn completely 1L of  propane gas (C₃H₈) measured under the same conditions?

1. 7L 

2. 6L

3. 5L

4. 10L

1 g of magnesium is burnt with 0.56g of oxygen in a closed vessel. The left-out reactant and its quantity are

(At. weight of Mg = 24, O=16)

Percentage of Se in peroxidase anhydrase enzyme is 0.5% by weight (at. weight = 78.4), then minimum molecular weight of peroxidase anhydrase enzyme is

1. 1.568 x 10³ 

2. 15.68

3. 2.168 x 10⁴ 

4. 1.568 x 10⁴ 

Number of moles of Mn${\mathrm{O}}_4^{-}$ required to oxidise one mole of ferrous oxalate completely in acidic medium will be 

1. 0.6 mole

2. 0.4 mole

3. 7.5 moles

4. 0.2 mole

The total number of valence electrons in 4.2g of ${\mathrm{N}}_3^{-}$ ion is (N_A is the Avogadro's number)

1. 2.1N_A 

2. 4.2N_A 

3. 1.6N_A 

4. 3.2N_A 

When 22.4L of H₂(g) is mixed with 11.2L of Cl₂(g) each at STP, the moles of HCl(g) formed is equal to 

1. 1 mole of HCl(g)

2. 2 moles of HCl(g)

3. 0.5 mole of HCl(g)

4. 1.5 moles of  HCl(g)

The mass of carbon anode consumed (giving only carbon dioxide) in the production of 270 kg of aluminium metal from bauxite by the Hall process is (at. mass of Al = 27)

1. 180 kg

2. 270 kg

3. 540 kg

4. 90 kg