You visited us 2 times! Enjoying our articles? Unlock Full Access!

Byju's Answer

Standard IX

Chemistry

Hydronium Ion

A water sampl...

Question

A water sample has a pH of 9.25. The concentration of hydroxyl ions in the water sample is

3.020 m g / L

No worries! We‘ve got your back. Try BYJU‘S free classes today!

10^{- 4.75} m m o l e s / L

No worries! We‘ve got your back. Try BYJU‘S free classes today!

10^{- 9.25} m o l e s / L

No worries! We‘ve got your back. Try BYJU‘S free classes today!

0.302 m g / L

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

Open in App

Solution

The correct option is D $0.302 m g / L$
$p H = 9.25$

We know,

$p H + p O H = 14$

$p O H = 14 - 9.25 = 4.75$

$[O H^{-}] = 10^{- p O H}$

$= 10^{- 4.75} m o l / / l i t r e$

Molecular weight of
$O H^{-} = 17 g$

Concentration of hydroxyl ions
$= 17 \times 10^{- 4.75} g / L$
$= 17 \times 10^{- 4.75} \times 1000 m g / L$
$= 0.302 m g / L$

Suggest Corrections

Similar questions

Q. The concentration of

O H^{-}

ion in a water sample is measured as 17 mg/L at

25^{\circ}

C. What is the pH of the water sample?

Q. The iron product of water

p K_{w}

is 14. If a rain water sample has a pH of 5.6, the concentration of

O H^{-}

in the sample (in

10^{- 9}

mol/litre, round off to one decimal place), is____

Q. A sample of hard water contains

96 ppm

S O 4_{4}^{2 -}

ions,

183 ppm

H C O_{3}^{-}

ions and the only cation present is

C a^{2 +}

X

moles of

C a O

are required to remove the

H C O_{3}^{-}

ions from

1000 kg

of this sample of water. When the same amount of

C a O

is added to the water sample, the concentration of residual

C a^{2 +}

ions (in ppm) becomes Y.
(Assume

C a C O_{3}

to be completely insoluble in water)
If the residual

C a^{2 +}

ions in

1 L

of the above -mentioned water sample is completely replaced by hydrogen ions, what will the

p H

of the resultant sample of hard water?

Q. The

C a^{2 +}

concentration and

M g^{2 +}

concent-ration of a water sample are

160 m g / l i t

and

40 m g / l i t

as their ions respectively. The total hardness of this water sample in terms of

C a C O_{3}

m g / l i t

is approximately equal to

Q. Ion concentration in water sample obtained from well is tabulated below

Ion	Ca++	Mg++	Na+	$H C O_{3}^{-}$	$S O_{4}^{- -}$
Concentration $(\frac{m g}{l})$	84	10	16	220	42

Total hardness (in

\frac{m g}{l} a s C a C O_{3})

of the water sample is____

Join BYJU'S Learning Program

A water sample has a pH of 9.25. The concentration of hydroxyl ions in the water sample is

The correct option is D 0.302mg/LpH=9.25 We know, pH+pOH=14 pOH=14−9.25=4.75 [OH−]=10−pOH =10−4.75mol//litre Molecular weight of OH−=17g Concentration of hydroxyl ions =17×10−4.75g/L =17×10−4.75×1000mg/L =0.302mg/L