Some Basic Concepts of Chemistry

The value of $\mathbf x$ is ____.

The value of $\mathbf y$ is ____.

The value of $\mathbf x$ is ____.

The value of $\mathbf y$ is ____.

4.5 g of compound A (MW = 90) was used to make 250 mL of its aqueous solution. The molarity of the solution in M is $x\times10^{-1}$. The value of $x$ is _______. (Rounded off to the nearest integer)

5.00 mL of 0.10 M oxalic acid solution taken in a conical flask is titrated against NaOH from a burette using phenolphthalein indicator. The volume of NaOH required for the appearance of permanent faint pink color is tabulated below for five experiments. What is the concentration, in molarity, of the NaOH solution?

Aluminium reacts with sulfuric acid to form aluminium sulfate and hydrogen. What is the volume of hydrogen gas in liters (L) produced at 300 K and 1.0 atm pressure, when 5.4 g of aluminium and 50.0 mL of 5.0 M sulfuric acid are combined for the reaction?

(Use molar mass of aluminium as $27.0\ \mathrm{g\,mol^{-1}}$, $R = 0.082\ \mathrm{atm\,L\,mol^{-1}\,K^{-1}}$)

$\ce{^{238}_{92}U}$ is known to undergo radioactive decay to form $\ce{^{206}_{82}Pb}$ by emitting alpha and beta particles. A rock initially contained $68\times10^{-6}$ g of $\ce{^{238}_{92}U}$. If the number of alpha particles that it would emit during its radioactive decay of $\ce{^{238}_{92}U}$ to $\ce{^{206}_{82}Pb}$ in three half-lives is $Z\times10^{18}$, then what is the value of $Z$?

Consider the reaction sequence from P to Q shown below. The overall yield of the major product Q from P is 75%. What is the amount in grams of Q obtained from 9.3 mL of P? (Use density of P = 1.00 g mL⁻¹; Molar mass of C = 12.0, H = 1.0, O = 16.0 and N = 14.0 g mol⁻¹)

The mole fraction of urea in an aqueous urea solution containing 900 g of water is 0.05. If the density of the solution is 1.2 g cm⁻³, the molarity of urea solution is ______

(Given data: Molar masses of urea and water are 60 g mol⁻¹ and 18 g mol⁻¹, respectively)

The ammonia prepared by treating ammonium sulphate with calcium hydroxide is completely used by $\ce{NiCl2.6H2O}$ to form a stable coordination compound. Assume that both the reactions are 100% complete. If 1584 g of ammonium sulphate and 952 g of $\ce{NiCl2.6H2O}$ are used in the preparation, the combined weight (in grams) of gypsum and the nickel-ammonia coordination compound thus produced is ______.

(Atomic weights in g mol⁻¹: H = 1, N = 14, O = 16, S = 32, Cl = 35.5, Ca = 40, Ni = 59)

Galena (an ore) is partially oxidized by passing air through it at high temperature. After some time, the passage of air is stopped, but the heating is continued in a closed furnace such that the contents undergo self-reduction. The weight (in kg) of Pb produced per kg of $\mathrm{O_2}$ consumed is ____.

(Atomic weights in g mol$^{-1}$: O = 16, S = 32, Pb = 207)

To measure the quantity of $\mathrm{MnCl_2}$ dissolved in an aqueous solution, it was completely converted to $\mathrm{KMnO_4}$ using the reaction,

$$\mathrm{MnCl_2 + K_2S_2O_8 + H_2O \rightarrow KMnO_4 + H_2SO_4 + HCl} \quad \text{(equation not balanced)}.$$

Few drops of concentrated HCl were added to this solution and gently warmed. Further, oxalic acid (225 mg) was added in portions till the colour of the permanganate ion disappeared. The quantity of $\mathrm{MnCl_2}$ (in mg) present in the initial solution is ____.

(Atomic weights in g mol$^{-1}$: Mn = 55, Cl = 35.5)

In the following reaction sequence, the amount of D (in g) formed from 10 moles of acetophenone is ____.

(Atomic weights in g mol$^{-1}$: H = 1, C = 12, N = 14, O = 16, Br = 80. The yield (%) corresponding to the product in each step is given in the parenthesis)

Acetophenone → [NaOBr; H$_3$O$^+$] → A (60%) → [NH$_3$, Δ] → B (50%) → [Br$_2$/KOH] → C (50%) → [Br$_2$ (3 equiv), AcOH] → D (100%)

1 gram of a carbonate ($\ce{M2CO3}$) on treatment with excess HCl produces 0.01186 mole of $\ce{CO2}$. The molar mass of $\ce{M2CO3}$ in g mol$^{-1}$ is :

The most abundant elements by mass in the body of a healthy human adult are : Oxygen (61.4%); Carbon (22.9%), Hydrogen (10.0%); and Nitrogen (2.6%). The weight which a 75 kg person would gain if all $^1$H atoms are replaced by $^2$H atoms is :

On treatment of 100 mL of 0.1 M solution of $\ce{CoCl3.6H2O}$ with excess $\ce{AgNO3}$; $1.2\times10^{22}$ ions are precipitated. The complex is :

Excess of NaOH (aq) was added to 100 mL of $\ce{FeCl3}$ (aq) resulting into 2.14 g of $\ce{Fe(OH)3}$. The molarity of $\ce{FeCl3}$ (aq) is :

(Given molar mass of Fe = 56 g mol$^{-1}$ and molar mass of Cl = 35.5 g mol$^{-1}$)

What quantity (in mL) of a 45% acid solution of a mono-protic strong acid must be mixed with a 20% solution of the same acid to produce 800 mL of a 29.875% acid solution ?

The mole fraction of a solute in a solution is 0.1. At 298 K, molarity of this solution is the same as its molality. Density of this solution at 298 K is $2.0\ \mathrm{g\,cm^{-3}}$. The ratio of the molecular weights of the solute and solvent, $\left(\dfrac{MW_{solute}}{MW_{solvent}}\right)$, is