Assign oxidation number to the underlined elements in each of the following species:
(a) NaH2PO4
(b) NaHSO4
(c) H4P2O7
(d) K2MnO4
(e) CaO2
(f) NaBH4
(g) H2S2O7
(h) KAl(SO4)2.12 H2O
(a) NaH2PO4
Let's assume oxidation number of P is x.
We know that,
Oxidation number of Na = +1
Oxidation number of H = +1
Oxidation number of O = -2
Then we have
1(+1) + 2(+1) + 1 (x) + 4(-2) = 0
⇒ 1 + 2 + x - 8 = 0
⇒ x - 5 = 0
⇒ x = + 5
Hence, oxidation number of P is +5
(b) NaHSO4
Let's assume oxidation number of S is x.
Oxidation number of Na = +1
Oxidation number of H = +1
Oxidation number of O = -2
Then we have:
1(+1) + 1(+1) + 1 (x) + 4(-2) = 0
⇒ 1 + 1 + x - 8 = 0
⇒ x-6 = 0
⇒ x = +6
Hence, oxidation number of S is +6
(c) H4P2O7
Let's assume oxidation number of P is x.
Oxidation number of H = +1
Oxidation number of O = -2
Then we have:
4(+1) + 2(x) + 7 (-2) = 0
⇒ 4 + 2x - 14 = 0
⇒ 2x - 10 = 0
⇒ 2x = +10
⇒ x = +5
Hence, Oxidation number of P is +5
(d) K2MnO4
Let's assume oxidation number of Mn is x.
Oxidation number of K = +1
Oxidation number of O = -2
Then we have:
2(+1) + 1(x) + 4 (-2) = 0
⇒ 2 + x - 8 = 0
⇒ x - 6 = 0
⇒ x = +6
Hence, Oxidation number of Mn is +6
(e) CaO2
Let's assume oxidation number of O is x.
Oxidation number of Ca = +2
Then we have:
1(+2) + 2(x) = 0
⇒ 2 + 2x = 0
⇒ 2x = -2
⇒ x = -1
Hence, Oxidation number of O is -1
(f) NaBH4
Let's assume oxidation number of B is x.
Oxidation number of Na = +1
Oxidation number of H = -1
Then we have:
1(+1) + 1(x) + 4(-1) = 0
⇒ 1 + x -4 = 0
⇒ x - 3 = 0
⇒ x = +3
Hence, Oxidation number of B is +3.
(g) H2S2O7
Let's assume oxidation number of S is x.
Oxidation number of O = -2
Oxidation number of H = +1
Then we have:
2(+1) + 2(x) + 7(-2) = 0
⇒ 2 + 2x - 14 = 0
⇒ 2x - 12 = 0
⇒ x = +6
Hence, Oxidation number of S is +6.
(h) KAl(SO4)2.12 H2O
Let's assume oxidation number of S is x.
Oxidation number of K = +1
Oxidation number of Al = +3
Oxidation number of O = -2
Oxidation number of H = +1
Then we have:
1(+1) + 1 (+3) + 2(x) + 8(-2) + 24(+1) + 12 (-2) = 0
⇒ 1 + 3 + 2x -16 +24 -24 = 0
⇒ 2x - 12 = 0
⇒ 2x = +12
⇒ x = +6
Hence, Oxidation number of S is +6.
The mass of an electron is 9.1 × 10–31 kg. If its K.E. is 3.0 × 10–25 J, calculate its wavelength.
Calculate the amount of carbon dioxide that could be produced when
(i) 1 mole of carbon is burnt in air.
(ii) 1 mole of carbon is burnt in 16 g of dioxygen.
(iii) 2 moles of carbon are burnt in 16 g of dioxygen.
Calculate the wavelength of an electron moving with a velocity of 2.05 × 107 ms–1.
Balance the following redox reactions by ion – electron method :
(a) MnO4 – (aq) + I – (aq) → MnO2 (s) + I2(s) (in basic medium)
(b) MnO4 – (aq) + SO2 (g) → Mn2+ (aq) + HSO4– (aq) (in acidic solution)
(c) H2O2 (aq) + Fe 2+ (aq) → Fe3+ (aq) + H2O (l) (in acidic solution)
(d) Cr2O7 2– + SO2(g) → Cr3+ (aq) + SO42– (aq) (in acidic solution)
In a process, 701 J of heat is absorbed by a system and 394 J ofwork is done by the system. What is the change in internal energy for the process?
What will be the minimum pressure required to compress 500 dm3 of air at 1 bar to 200 dm3 at 30°C?
In a reaction A + B2 → AB2 Identify the limiting reagent, if any, in the following reaction mixtures.
(i) 300 atoms of A + 200 molecules of B
(ii) 2 mol A + 3 mol B
(iii) 100 atoms of A + 100 molecules of B
(iv) 5 mol A + 2.5 mol B
(v) 2.5 mol A + 5 mol B
At 0°C, the density of a certain oxide of a gas at 2 bar is same as that of dinitrogen at 5 bar. What is the molecular mass of the oxide?
Which one of the following will have largest number of atoms?
(i) 1 g Au (s)
(ii) 1 g Na (s)
(iii) 1 g Li (s)
(iv) 1 g of Cl2(g)
Density of a gas is found to be 5.46 g/dm3 at 27 °C at 2 bar pressure. What will be its density at STP?
What is the lowest value of n that allows g orbitals to exist?
Assuming complete dissociation, calculate the pH of the following solutions:
(a) 0.003 M HCl
(b) 0.005 M NaOH
(c) 0.002 M HBr
(d) 0.002 M KOH
Write the formulae for the following compounds:
(a) Mercury(II) chloride
(b) Nickel(II) sulphate
(c) Tin(IV) oxide
(d) Thallium(I) sulphate
(e) Iron(III) sulphate
(f) Chromium(III) oxide
Why is LiF almost insoluble in water whereas LiCl soluble not only in water but also in acetone?
Calculate the oxidation number of sulphur, chromium and nitrogen in H2SO5, Cr2O2- 7 and NO– 3. Suggest structure of these compounds. Count for the fallacy.
Calculate the pH of the following solutions:
(a) 2 g of TlOH dissolved in water to give 2 litre of solution.
(b) 0.3 g of Ca(OH)2 dissolved in water to give 500 mL of solution.
(c) 0.3 g of NaOH dissolved in water to give 200 mL of solution.
(d) 1mL of 13.6 M HCl is diluted with water to give 1 litre of solution.
Which one of the alkaline earth metal carbonates is thermally the most stable?
(a) MgCO3 (b) CaCO3 (c) SrCO3 (d) BaCO3
What is the maximum number of emission lines when the excited electron of an H atom in n = 6 drops to the ground state?
The mass of an electron is 9.1 × 10–31 kg. If its K.E. is 3.0 × 10–25 J, calculate its wavelength.
In Milikan’s experiment, static electric charge on the oil drops has been obtained by shining X-rays.
If the static electric charge on the oil drop is –1.282 × 10–18C, calculate the number of electrons present on it.
Gud to disclose all the answers .anyway thanks