Give one significant observation when: (a) Barium chloride solution is added to zinc sulphate solution. (b) Lead nitrate is heated strongly. (c) Chlorine gas is passed through moist starch iodide paper.

You are provided with some compounds in the box. PbO CH4 PbO2 CO2 HCl NCl3 SO2 Choose the most appropriate compound which fits the descriptions (a) to (c) given below: (a) A colourless gas which turns acidified K2Cr2O7 from orange to green. (b) A yellow explosive oily liquid formed when excess chlorine gas reacts with ammonia gas. (c) A yellow metallic oxide formed on thermal decomposition of PbCO3.

Rita added dilute hydrochloric acid to four metals. She recorded her observations in the table given below. While noting her observations she made some errors. Metals Observations 1 copper a gas was given off 2 iron a gas was given off 3 magnesium no gas was given off 4 zinc a gas was given off Which observation(s) made by Rita is/are correct? (a) 1 only (b) 3 only (c) Both 1 and 4 (d) Both 2 and 4

Choose the substances given in the box below to answer the following questions: Iron Magnesium sulphite Zinc Sodium sulphide Lead Ferric chloride Copper Ferrous sulphate (a) The metal that will not produce hydrogen gas when reacted with dilute acids. (b) The compound that will produce sulphur dioxide gas when reacted with dilute HCl. (c) The solution of this compound produces dirty green precipitate with NaOH.

K, L and M are beakers containing three different solutions as shown below. Name the beaker which: (a) contains only ions. (b) contains only molecules. (c) has pH less than 7.

Elements P, Q, and R are in the same period of the modern periodic table. P readily loses its one valence electron to form a stable ion. Q shares its electrons in bonding but does not form ions easily. R has high electronegativity. Answer the following questions based on the above information: (a) Which element would be most difficult to reduce among P, Q and R? (b) Which element is expected to have the smallest atomic radius among P, Q and R? (c) Arrange P, Q and R in order of decreasing ionisation potential.

Given below are a few elements. Li, Li, K, Ca, F Identify the element which: (a) has the least atomic radius. (b) has two valence electrons. (c) is the most electropositive.

Zn + 4HNO3 ⟶ Zn(NO3)2 + 2H2O + 2NO2 32.5 g of zinc reacts with concentrated nitric acid as given in the above equation. (a) How many moles of zinc was required in the reaction? (b) Find the mass of nitric acid needed to react with 32.5 g of zinc. (c) Find the volume of nitrogen dioxide liberated in (b). [Atomic weight: H=1, N=14, O=16, Zn=65]

Anil is a laboratory assistant in a college. He prepared nitric acid but stored it in a transparent container exposed to sunlight. After a few days, brown fumes were observed in the container and the acid turned slightly yellowish in colour. (a) What was the error made by Anil while storing the acid? (b) Why were brown fumes observed in the container? (c) How can the yellowish tinge in the acid be removed?

During the manufacture of sulphuric acid, a chemist collected the gas formed after catalytic oxidation of sulphur dioxide. (a) Name the gas collected. (b) Which acid is formed when the gas collected by the chemist is dissolved directly in water? (c) Why should we not dissolve this gas directly in water?

Complete and balance the following equations: (a) C2H4Br2 + KOH (alcoholic) ⟶ (b) NH3 (excess) + Cl2 ⟶ (c)

Study the reaction scheme shown below and identify the reactants A, B and C.