A water is said to be soft water if it produces sufficient foam with the soap and water that does not produce foam with soap is known as hard water. Hardness has been classified into two types (i)Temporary hardness (ii) Permanent hardness. Temporary hardness is due to presence of calcium and magnesium bicarbonate. It is simply removed by boiling as `Ca(HCO_(3))_(2)overset(Delta)rarr CaCO_(3)darr+CO_(2)uarr+H_(2)O` `Mg(HCO_(3))_(2)overset(Delta)rarr MgCO_(3)darr+CO_(2)uarr+H_(2)O` temporary hardness can also be removed by addition of slaked lime, `Ca(OH)_(2)` `Ca(HCO_(3))_(2)+Ca(OH)_(2)to2CaCO_(3)darr+2H_(2)O` permanent hardsness is due to presencce of sulphates and chlorides of Ca,Mg,etc. It is removed by washing soda as `CaCl_(2)+Na_(2)CO_(3)toCaCO_(3)darr+2NaCl` `CaSO(4)+Na_(2)CO_(3)to CaCO_(3)darr+Na_(2)SO_(4)` Permanent hardness also removed by ion exchange resin process as `2RH+Ca^(2+) to R_(2)Ca+2H^(+)` `2ROH+SO_(4)^(2-)toR_(2)SO_(4)+2OH^(-)` The degree of hardness of water is measured in terms of PPm of `CaCO_(3)` 100 PPm means 100 g of `CaCO_(3)` is present in `10^(6)` g of `H_(2)O`. If any other water sample which contain 120 PPm of `MgSO_(4)`, hardness in terms of `CaCO_(3)` is equal to =100 PPm. What is the mass of `Ca(OH)_(2)` required for 10 litre of water remove temporary hardness of 100 PPm due to `Ca(HCO_(3))_(2)` ?A. 1.62 gB. 0.74 gC. 7.4 gD. None of these

A water is said to be soft water if it produces sufficient foam with t

1.	A water is said to be soft water if it produces sufficient foam with the soap and water that does not produce foam with soap is known as hard water. Hardness has been classified into two types (i)Temporary hardness (ii) Permanent hardness. Temporary hardness is due to presence of calcium and magnesium bicarbonate. It is simply removed by boiling as `Ca(HCO_(3))_(2)overset(Delta)rarr CaCO_(3)darr+CO_(2)uarr+H_(2)O` `Mg(HCO_(3))_(2)overset(Delta)rarr MgCO_(3)darr+CO_(2)uarr+H_(2)O` temporary hardness can also be removed by addition of slaked lime, `Ca(OH)_(2)` `Ca(HCO_(3))_(2)+Ca(OH)_(2)to2CaCO_(3)darr+2H_(2)O` permanent hardsness is due to presencce of sulphates and chlorides of Ca,Mg,etc. It is removed by washing soda as `CaCl_(2)+Na_(2)CO_(3)toCaCO_(3)darr+2NaCl` `CaSO(4)+Na_(2)CO_(3)to CaCO_(3)darr+Na_(2)SO_(4)` Permanent hardness also removed by ion exchange resin process as `2RH+Ca^(2+) to R_(2)Ca+2H^(+)` `2ROH+SO_(4)^(2-)toR_(2)SO_(4)+2OH^(-)` The degree of hardness of water is measured in terms of PPm of `CaCO_(3)` 100 PPm means 100 g of `CaCO_(3)` is present in `10^(6)` g of `H_(2)O`. If any other water sample which contain 120 PPm of `MgSO_(4)`, hardness in terms of `CaCO_(3)` is equal to =100 PPm. What is the mass of `Ca(OH)_(2)` required for 10 litre of water remove temporary hardness of 100 PPm due to `Ca(HCO_(3))_(2)` ?A. 1.62 gB. 0.74 gC. 7.4 gD. None of these
Answer» Correct Answer - B

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The purity of `H_2O_2` in a given sample is `85%.` Calculate the weight of impure sample of `H_2O_2` which requires `10mL` of `M//5 KMnO_4` solution in a titration in acidic mediumA. 2 gB. 0.2 gC. 0.17 gD. 0.15 g
An impure sample of sodium oxalate `(Na_(2)C_(2)O_(4)` weighing 0.20 g is dissolved in aqueous solution of `H_(2)SO_94)` and solution is titrated at `70^(@)C`,requiring 45 mL of 0.02 M `KMnO_(4)` solution. The end point is overrun, and back titration in carried out with 10 mL of 0.1 M oxalic acid solution.Find the purity of `Na_(2)C_(2)O_(4)` in sample:A. 75B. 83.75C. 90.25D. None of these
`60ml` of mixture of equal volumes of `Cl_(2)` and an oxide of chloine, i.e., `Cl_(2)O_(n)` was heated and then cooled back to the original temperature. The resulting gas mixture was found to have volume of `75ml`. On treatment with `KOH` solution, the volume contracted to `15ml`. Assume that all measurements are made at the same temperature and pressure. Deduce the value of `n` in `Cl_(2)O_(n)`. The oxide of `Cl_(2)` n heating decomposes quantiatively to `O_(2)` and `Cl_(2)`.
`12. g` of an impure sample of arsenious oxide was dissolved in water containing `7.5 g` of sodium bicarbonate and the resulting solution was diluted to `250 mL`. `25 mL` of this solution was completely oxidised by `22.4 mL` of a solution of iodine. `25 mL` of this iodine solution reacted with same volume of a solution containing `24.8 g` of sodium thiosulphate `(Na_(2)S_(2)O_(3).5H_(2)O)` in one litre. Calculate teh percentage of arsenious oxide in the sample ( Atomic mass of `As=74`)
`K_(2)Cr_(2)O_(7)` is obtained in the following steps: `2FeCrO_(4)+2Na_(2)CO_(3)+OtoFe_(2)O_(3)+2Na_(2)CrO_(4)+2CO_(2)` `2Na_(2)CrO_(4)+H_(2)SO_(4)toNa_(2)Cr_(2)O_(7)+H_(2)O+Na_(2)SO_(4)` `Na_(2)Cr_(2)O_(7)+2KCltoK_(2)Cr_(2)+2NaCl` To get 0.25 " mol of "`K_(2)Cr_(2)O_(7)`, " mol of "`50%` pure `FeCrO_(4)` required.A. 1 molB. 0.50 molC. 0.25 molD. 0.125 mol
How many moles of `O_(2)` will be liberated by one mole of `CrO_(5)` is the following reaction: `CrO_(5) + H_(2) SO_(4) rarr Cr_(2) (SO_(4))_(3) + H_(2)O + O_(2)`A. `(5)/(2)`B. `(5)/(4)`C. `(9)/(2)`D. none of these
A sample containing 0.4775 of `(NH_(4))_(2)C_(2)O_(4)` and inert material was dissolved in water and made strongly alkaline with KOH which converted `NH_(4)^(o+)` to `NH_(3)` The liberated `NH_(3)` was distilled of `H_(2)SO_(4)` was back titrated with 11.3 " mL of " 0.1214 M NaOH. Calculate (a) `% of (NH_(4))_(2)C_(2)O_(4)=124.10` And atomic weight of `N=14.0078`.
2.0 g sample of NaCN is dissolved in 50 " mL of " 0.3 M mild alkaline `KMnO_(4)` and heated strongly to convert all the `CN^(ɵ)` to `OCN^(ɵ)`. The solution after acidification with `H_(2)SO_(4)` requries 500 " mL of " 0.05 M `FeSO_(4)` Calculate the percentage purity of NaCN in the sample.
10 " mL of " `NaHC_(2)O_(4)` is oxidised by 10 " mL of " 0.02 M `MnO_(4)^(ɵ)`. Hence, 10 " mL of " `NaHC_(2)O_(4)` is neutralised byA. 10 " mL of " 0.1 M NaOHB. 10 " mL of " 0.02 M NaOHC. 10 " mL of " 0.1 M `Ca(OH)_(2)`D. 10 " mL of " 0.05 N `Ba(OH)_(2)`
`CN^(ɵ)` is oxidised by a strong oxidising agent to `NO_3^(ɵ)` and `CO_2` or `CO_3^(2-)` depending upon the acidity of the reaction mixture. `HNO_3` a strong oxidising agent is reduced by a moderate reducing agent to NO. Write the balanced equation of `HNO_3` with KCN. `CH^(ɵ)toCO_2+NO_3^(ɵ)` `NO_3^(ɵ)NO` If this reaction is carried out, what safety precautions are required?

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