On addition of conc. H2SO4 to a chloride salt, colourless fumes are evolved but in case of iodide salt, violet fumes come out. This is because
In qualitative analysis when H2S is passed through an aqueous solution of salt acidified with dil. HCl, a black precipitate is obtained. On boiling the precipitate with dil. HNO3, it forms a solution of blue colour. Addition of excess of aqueous solution of ammonia to this solution gives _________.
In a cyclotrimetaphosphoric acid molecule, how many single and double bonds are present?
Which of the following elements can be involved in pp–dp bonding?
Which of the following pairs of ions are isoelectronic and isostructural?
Affinity for hydrogen decreases in the group from fluorine to iodine. Which of the halogen acids should have highest bond dissociation enthalpy?
Bond dissociation enthalpy of E—H (E = element) bonds is given below. Which of the compounds will act as strongest reducing agent?
On heating with concentrated NaOH solution in an inert atmosphere of CO2, white phosphorus gives a gas. Which of the following statement is incorrect about the gas?
Which of the following acids forms three series of salts?
Strong reducing behavior of H3PO2 is due to
On heating lead nitrate forms oxides of nitrogen and lead. The oxides formed are ______.
Which of the following elements does not show allotropy?
Maximum covalency of nitrogen is ______________.
Which of the following statements is wrong?
A brown ring is formed in the ring test for NO3
– ion. It is due to the formation of
Elements of group-15 form compounds in +5 oxidation state. However, bismuth forms only one well characterisedcompound in +5 oxidation state. The compound is
On heating ammonium dichromate and barium azide separately we get
In the preparation of HNO3, we get NO gas by catalytic oxidation of ammonia. The moles of NO produced by the oxidation of two moles of NH3 will be ______.
The oxidation state of central atom in the anion of compound NaH2PO2 will be ______.
Which of the following is not tetrahedral in shape?
Which of the following are peroxoacids of sulphur?
Hot conc. H2SO4 acts as moderately strong oxidising agent. It oxidises both metals and nonmetals. Which of the following element is oxidised by conc. H2SO4 into two gaseous products?
A black compound of manganese reacts with a halogen acid to give greenish yellow gas. When excess of this gas reacts with NH3 an unstable trihalide is formed. In this process the oxidation state of nitrogen changes from _________.
In the preparation of compounds of Xe, Bartlett had taken O2+Pt F6– as a base compound. This is because
In solid state PCl5 is a _________.
Reduction potentials of some ions are given below. Arrange them in decreasing order of oxidising power.
Which of the following is isoelectronic pair?
If chlorine gas is passed through hot NaOH solution, two changes are observed in the oxidation number of chlorine during the reaction. These are ________ and _________.
Which of the following options are not in accordance with the property mentioned against them?
Which of the following is correct for P4 molecule of white phosphorus?
Which of the following statements are correct?
Which of the following statements are correct for SO2 gas?
Which of the following orders are correct as per the properties mentioned against each?
In which of the following reactions conc. H2SO4 is used as an oxidising reagent?
Which of the following statements are true?
In the preparation of H2SO4 by Contact Process, why is SO3 not absorbed directly in water to form H2SO4?
Write a balanced chemical equation for the reaction showing catalytic oxidation of NH3 by atmospheric oxygen.
Write the structure of pyrophosphoric acid.
PH3 forms bubbles when passed slowly in water but NH3 dissolves. Explain why?
In PCl5, phosphorus is in sp3d hybridised state but all its five bonds are not equivalent. Justify your answer with reason.
Why is nitric oxide paramagnetic in gaseous state but the solid obtained on cooling it is diamagnetic?
Give reason to explain why ClF3 exists but FCl3 does not exist.
Out of H2O and H2S, which one has higher bond angle and why?
SF6 is known but SCl6 is not. Why?
On reaction with Cl2, phosphorus forms two types of halides ‘A’ and ‘B’. Halide A is yellowish-white powder but halide ‘B’ is colourless oily liquid. Identify A and B and write the formulas of their hydrolysis products.
In the ring test of NO3– ion, Fe2+ ion reduces nitrate ion to nitric oxide, which
combines with Fe2+ (aq) ion to form brown complex. Write the reactions involved in the formation of brown ring.
Explain why the stability of oxoacids of chlorine increases in the order given below:
HClO< HClO2< HClO3< HClO4
Explain why ozone is thermodynamically less stable than oxygen.
P4O6 reacts with water according to equation P4O6 + 6H2O → 4H3PO3.
Calculate the volume of 0.1 M NaOH solution required to neutralise the acid formed by dissolving 1.1 g of P4O6 in H2O.
White phosphorus reacts with chlorine and the product hydrolyses in the presence of water. Calculate the mass of HCl obtained by the hydrolysis of the product formed by the reaction of 62 g of white phosphorus with chlorine in the presence of water.
Name three oxoacids of nitrogen. Write the disproportionation reaction of that oxoacid of nitrogen in which nitrogen is in +3 oxidation state.
Nitric acid forms an oxide of nitrogen on reaction with P4O10. Write the reaction involved. Also write the resonating structures of the oxide of nitrogen formed.
Phosphorus has three allotropic forms — (i) white phosphorus (ii) red phosphorus and (iii) black phosphorus. Write the difference between white and red phosphorus on the basis of their structure and reactivity.
Give an example to show the effect of concentration of nitric acid on theformation of oxidation product.
PCl5 reacts with finely divided silver on heating and a white silver salt is obtained, which dissolves on adding excess aqueous NH3 solution. Write the reactions involved to explain what happens.
Phosphorus forms a number of oxoacids. Out of these oxoacidsphosphinicacid has strong reducing property. Write its structure and also write a reaction showing its reducing behaviour.
Match the compounds given in Column I with the hybridisation and shape given in Column II and mark the correct option.
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Match the formulas of oxides given in Column I with the type of oxide given in Column II and mark the correct option.
Match the items of Columns I and II and mark the correct option.
Match the species given in Column I with the shape given in Column II and mark the correct option.
Note : In the following questions a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
An amorphous solid “A” burns in air to form a gas “B” which turns lime water milky. The gas is also produced as a by-product during roasting of sulphideore. This gas decolourises acidified aqueous KMnO4 solution and reduces Fe3+ to Fe2+. Identify the solid “A” and the gas “B” and write the reactions involved.
On heating lead (II) nitrate gives a brown gas “A”. The gas “A” on cooling changes to colourless solid “B”. Solid “B” on heating with NO changes to a blue solid ‘C’. Identify ‘A’, ‘B’ and ‘C’ and also write reactions involved and draw the structures of ‘B’ and ‘C’.
On heating compound (A) gives a gas (B) which is a constituent of air. This gas when treated with 3 mol of hydrogen (H2) in the presence of a catalyst gives another gas (C) which is basic in nature. Gas C on further oxidation in moist condition gives a compound (D) which is a part of acid rain. Identify compounds (A) to (D) and also give necessary equations of all the steps involved.
