Some Basic Concepts of Chemistry · Question 15

14.0 g of calcium metal is allowed to react with excess HCl at 1.0 atm pressure and 273 K. Which of the following statements is incorrect? [Given : Molar mass in g mol-1 of Ca – 40, Cl – 35.5, H – 1]

1. The limiting reagent is calcium metal.
2. 33.3 g of CaCl2 is produced.
3. 7.84 L of H2 gas is evolved.
4. 0.35 mol of H2 gas is evolved.

80 mL of a hydrocarbon on mixing with 264 mL of oxygen in a closed U-tube undergoes complete combustion. The residual gases after cooling to 273 K occupy 224 mL. When the system is treated with KOH solution, the volume decreases to 64 mL. The formula of the hydrocarbon is :

1. C2H2
2. C2H4
3. C4H10
4. C2H6

Aqueous HCl reacts with MnO2(s) to form MnCl2(aq), Cl2(g), and H2O(l). What is the weight (in g) of Cl2 liberated when 8.7 g of MnO2(s) is reacted with excess aqueous HCl solution? (Given Molar mass in g mol-1 Mn = 55, Cl = 35.5, O = 16, H = 1)

1. 14.2
2. 21.3
3. 7.1
4. 71

20 mL of sodium iodide solution gave 4.74 g silver iodide when treated with excess of silver nitrate solution. The molarity of the sodium iodide solution is M. (Nearest Integer value) (Given : Na = 23, I = 127, Ag = 108, N = 14, O = 16 g mol-1)

Thyroxine, the hormone, has the structure given below [figure] The percentage of iodine in thyroxine is %. (nearest integer) (Given molar mass in g mol-1 C : 12, H : 1, O : 16, N : 14, I : 127)

Butane reacts with oxygen to produce carbon dioxide and water following the equation given below. C4H10(g) + 132O2(g) 4CO2(g) + 5H2O(l) If 174.0 kg of butane is mixed with 320.0 kg of O2, the volume of water formed in liters is . (Nearest integer) [Given : (a) Molar mass of C, H, O are 12, 1, 16 g mol-1 respectively, (b) Density of water = 1 g mL-1]

Fortification of food with iron is done using FeSO4 7H2O. The mass in grams of the FeSO4 7H2O required to achieve 12 ppm of iron in 150 kg of wheat is (Nearest integer) [Given: Molar mass of Fe, S and O respectively are 56, 32 and 16 g mol-1]

The amount of calcium oxide produced on heating 150 kg limestone (75% pure) is kg. (Nearest integer) Given: Molar mass (in g mol-1) of Ca-40, O-16, C-12

Among 10-9 g (each) of the following elements, which one will have the highest number of atoms? Element: Pb, Po, Pr and Pt

1. Pr
2. Pt
3. Po
4. Pb

Mass of magnesium required to produce 220 mL of hydrogen gas at STP on reaction with excess of dil. HCl is Given: Molar mass of Mg is 24 g mol-1.

1. 0.24 mg
2. 235.7 g
3. 2.444 g
4. 236 mg