Hardness of Water and Treatment

Q.

Temporary hardness of water is due to the presence of

1. Magnesium bicarbonate
2. Calcium chloride
3. Magnesium sulphate
4. Calcium carbonate

Q. Permanent hardness of water can be removed by adding calgon $(NaP{O}_3{)}_6$. This is an example of:

1. Adsorption
2. Exchange of ions
3. Precipitation
4. None of these

Q.

Name any one salt present in hard water.

Q. 41. 0.8 mole of a mixture of CO and CO2 exactly requires 40gram of NaOH in solution for complete conversion of all the CO2 into Na2CO3. How many moles more of NaOH would it require for conversion into Na2CO3, if the mixture (0.8mole)is completely oxidised to CO2?

Q. Which of the following salts will cause temporary hardness of water?

1. $Mg\left(HC{O}_3\right)$
2. $CaC{l}_2$
3. $MgC{l}_2$
4. $CaS{O}_4$

Q. 13 In faintly alkaline solution , 4 moles of permanganate anion quantitatively oxidize thiosulphate anions to produce X moles of sulphate anion. The magnitude of X is

Q. The equillibrium of formation of phosgene is represented as: The reaction is carried out in a 500mL flask, At equillibrium 0.3 mole of phosgene, 0.1 mole of CO and 0.1 mole of Cl_{2 } are present. The equillibrium cons†an t of the reactio n is: (a) 30 (b) 15 (c) 5 (d) 3

Q.

Identify the anion present in the compound Y is treated with Silver nitrate solution a white precipitate is obtained which is soluble in excess of Ammonium hydroxide solution?

Q. The exhausted permutit is generally regenerated by percolating through a solution of:

1. Sodium chloride
2. Calcium chloride
3. Magnesium chloride
4. Potassium chloride

Q. 1 litre of gaseous aliphatic compound CxHyOz is completely burnt in an excess of O2 and cooled to room temperature.The reacted volume of O2 will be?

Q.

1. boiling
2. filtration
3. distillation
4. decantation

Q. Permutit is the technical name given to

1. Aluminates of calcium and sodium
2. Hydrated silicate of aluminium and sodium
3. Silicates of calcium and magnesium
4. Silicates of calcium and sodium

Q. Which of the following is/are hard water(s)?

1. Water containing some potash alum

2. Water containing a few drops of HCl

3. Water containing common salt

4. Water containing calcium nitrate

Q. Are dil.hcl and conc.hcl oxidizing or reducing agents?

Q. What happens when sodium peroxide reacts with water ?

Q. Salt(s) which has acidic hydrogen, is (1) NaH_2PO_2 (2) Na_2HPO_3 (3) NaH_2PO_4 (4) All of these

Q. Different water samples A, B, C and D have 150 ppm each of $CaC{l}_2,MgS{O}_4,CaS{O}_{4}andMgC{l}_2$ respectively. The order of degree of hardness of these samples is

1. D > A > B > C
2. A > B > C > D
3. C > B > A > D
4. C > A > D > B

Q. Calculate the moles of Na2SO4 produced from 5 moles of NaOH 2NaOH + H2SO4 → Na2SO4 + 2H2O

Q.

Which of the following is a very important component of ceramics?

1. Carbon

2. Tin

3. Germanium

4. Silicon

Q. what is thermite process?

Q. Both temporary and permanent hardness is removed on boiling water with :-

1. $Ca(OH{)}_2$
2. $N{a}_{2}C{O}_3$
3. $CaC{O}_3$
4. $CaO$

Q. The reagent (s) that can be used for softening the Permanent hardness of water is (are)

1. Synthetic Resins
2. $Ca(OH{)}_2$
3. $N{a}_6{P}_6{O}_{18}$
4. Zeolites

Q. 26) Number of moles of MnO, required-to oxidize onemole of ferrous oxalate completely in acidic mediumwill be(1) 0.2 moles(2) 0.6 moles(3) 0.4 moles(4) 7.5 molesAIPMT (Prelims)-2008\rbrack

Q.

Clark's method of water softening uses:

1. Na₆P₆O₁₈

2. Ion exchange resin

3. Na₂CO₃

4. Ca(OH)₂

Q. In faintly alkaline solution, 4 moles ofpermanganate anion quantitatively oxidize thiosulphate anions to produce X moles of sulphate anion. The value of X is (1) 8 (2) 6 (3) 3 (4)

Q.

The reaction that takes place in the Clarke's process is

1. Ca(${HCO}_3$)${}_2$ $\to$ ${CaCO}_3$ + $H_2$O + ${CO}_2$

2. 2Ca($OH$)${}_2$ + Mg(${HCO}_3$)${}_2$ $\to$ 2${CaCO}_3$ + Mg($OH$)${}_2$ + 2$H_2$O

3. ${Na}_2$${Si}_2$$O_8$ + ${CaCl}_2$ $\to$ ${CaSi}_2$$O_8$ + 2NaCl

4. 2RCOOH + Mg${Cl}_2$→($RCOO{)}_2$Mg + 2HCl

Q.

Exhausted permutit is

1. CaAl₂Si₂O₈. xH₂O

2. K₂Al₂Si₂O₈.xH₂O

3. CaB₂Si₂O₈.xH₂O

4. Na₂Al₂Si₂O₈.xH₂O

Q.

Which of the following can be used to remove temporary hardness of water?

1. Nitrolim

2. Hydrolith

3. Plaster of Paris

4. Slaked Lime

Q. Calgon is an industrial name given to____________.

1. sodium meta-aluminate
2. sodium hexametaphosphate
3. hydrated sodium aluminium silicate
4. normal sodium phosphate

Q. $80mL$ of water sample contains $0.162gCa(HC{O}_3{)}_2$ and $0.146gMg(HC{O}_3{)}_2.$ The hardness of water expressed in term of $CaC{O}_3$ is:
(Given : molar mass of $Ca\left(HC{O}_3{)}_{2}andMg\right(HC{O}_3{)}_2$ are 162 and 146 g/mol respectively. )

1. $2.5\times {10}^{3}ppm$
2. $1.5\times {10}^{3}ppm$
3. $5\times {10}^{4}ppm$
4. $6.2\times {10}^{4}ppm$