Hardness of Water and Methods of Removing Hardness

Which of the following groups of ions makes the water hard?

Hardness of water is $200 \mathrm{ppm}.$ The normality of ${\mathrm{CaCO}}_3$ in the water is in the form of $\mathrm{y}\times {10}^{-3}.$ Identify $\mathrm{y}.$

Assertion (A) : Permanent hardness of water is removed by treatment with washing soda.

Reason (R) : Washing soda reacts with soluble magnesium and calcium sulphate to form insoluble carbonates.

Permanent hardness in water cannot be cured by:

Which one of the following processes produces hard water?

Washing soda $\left({\mathrm{Na}}_2{\mathrm{CO}}_3·10{\mathrm{H}}_2\mathrm{O}\right)$ is widely used in softening of hard water. If $1 \mathrm{L}$ of hard water requires $0.0143 \mathrm{g}$ of washing soda. What is hardness of water in terms of $\mathrm{ppm}$ of ${\mathrm{CaCO}}_3$ ?

Washing soda $\left({\mathrm{Na}}_2{\mathrm{CO}}_3·10{\mathrm{H}}_2\mathrm{O}\right)$ is widely used in softening of hard water. If $1 \mathrm{L}$ of hard water requires $0.0143 \mathrm{g}$ of washing soda. What is hardness of water in terms of $\mathrm{ppm}$ of ${\mathrm{CaCO}}_3$ ?

Which of the following is the reagent commonly used to determine the hardness of water by complexometric titration?

What necessary modification should be made in the synthetic resin method, so that the anion exchanger is not required?

Which one of the following processes produces hard water?

What necessary modification should be made in the synthetic resin method, so that the anion exchanger is not required?

Polyphosphates are used as water softening agents because they 

Which one of the following processes produces hard water?

Which of the following is the reagent commonly used to determine the hardness of water by complexometric titration?

Permanent hardness of water can be removed by 

Treatment with lime can remove hardness of water caused by

When temporary hard water containing magnesium and calcium hydrogen carbonate is boiled, the precipitate formed contains ________

Permanent hardness of water, due to the presence of ${\mathrm{MgSO}}_4,$can be removed by using ____________
(i) Washing soda.
(ii) Calgon's method.
(iii) Boiling.
(iv) Table salt.

Which of the following is not true ?