Chemistry Question Bank

In a compound C, H and N atoms are present as 9%, 1%, 3.5% respectively. Molecular weight of compound is 108. Molecular formula of compound is (a) C H N (b) C H N (c) C H N (d) C H N

When a hydrate of Na₂CO₃ is heated until all the water is removed, it loses 54.3 per cent of its mass. The formula of the hydrate is

A  27.0  g  sample  of  an  unknown  hydrocarbon  was burned in excess O₂ to form 88g of CO₂ and 27g of H₂O.  What  is  possible  molecular  formula  of hydrocarbon ?

Number  of  atoms  in  560g  of  Fe  (atomic  mass 56 g mol–1) is

If  we  consider  that  1/6,  in  place  of  1/12,  mass  of carbon  atom  is  taken  to  be  the  relative  atomic  mass unit, the mass of one mole of a substance will

P  and  Q  are  two  elements  which  forms  P₂Q3  and PQ2. If 0.15 mole of P₂Q3 weights 15.9g and 0.15 mole of PQ2 weights  9.3g, the atomic  weight  of P and Q is (respectively) :

100  mL  of  mixture  of  NaOH  and  Na₂SO₄  is neutralised  by  10  mL  of  0.5  M  H₂SO₄.  Hence, NaOH in 100 mL solution is

During the process of electrolytic refining of copper, some metals present as impurity settle as ‘anode mud’. These are

Assertion: Al₂O₃ is converted into Al by reduction with carbon at high temp. Reason: Carbon has greater affinity for oxygen than aluminium.

Assertion: Lead, tin and bismuth are purified by liquation method. Reason: Lead, tin and bismuth have low m.p. as compared to impurities.

Assertion: All the ores are mineral. Reason: Ores contains metals in combined state

Assertion: In the electrolytic reduction of Al₂O₃, cryolite is used. Reason: Cryolite is an ore of aluminium.

The two most abundant metals in the earth crust are:

Assertion: Wrought iron is more malleable and ductile than steel. Reason: It contains slightly less percentage of carbon.

Carbonate of which of the following metal does not liberate carbon dioxide on heating:

Assertion: In the extraction of Ag, complex Na [Ag (CN)₂] is reacted with Zn. Reason: Zn is d-block transition metal.

Assertion: Thermite mixture Fe₂O³⁺ Al (powder) is used in the welding. Reason: Al is a good reductant.

Assertion: Ores are generally converted into oxides, prior to reduction. Reason: Metal oxides can be easily reduced.

Assertion: In froth flotation process sodium ethyl xanthate is used as collector. Reason: Sulphide ores are water soluble.

The metal ores [X] and [Y] are respectively:

Which of the following statements is correct about [Y]?

Assertion: Extraction of iron metal from iron oxide ore is carried out by heating with coke. Reason: The reaction, Fe O (s) Fe(s)+ O (g) → is a spontaneous process.

Assertion: Cryolite is used in electrolytic extraction of Al from alumina. Reason: It dissolves alumina.

Among the following statements, the incorrect one is:

Assertion: CuFeS₂ is concentrated by froth floatation method. Reason: CuFeS₂ is main ore of copper.