# Tritium,T(an isotope of H) combines with F to form a weak acid TF, which ionizes to give  T+, Tritium is radioactive and is BETA-emitter. A freshly prepared solution of TF has pT (equivalent of pH) of 1.5 and freezes at -0.372 degree celcius . If 600 ml of freashly prepared solution were allowed to stand for 24.8 years, CALCULATE:(a) The ionization constant of  TF.(b) The number of beta - particles emitted

10 Points
14 years ago

Hi

Tritium , symbol T or 3H, also known as Hydrogen-3 is a radioactive isotope of hydrogen. The nucleus of tritium (sometimes called a triton) contains one proton and two neutrons, whereas the nucleus of protium (the most abundant hydrogen isotope) contains one proton and no neutrons.

β decay (electron emission)

Beta decay

An unstable atomic nucleus with an excess of neutrons may undergo β decay, where a neutron is converted into a proton, an electron and an electron-type antineutrino (the antiparticle of the neutrino):

np + e + νe

While tritium has several different experimentally-determined values of its half-life, the NIST recommends 4,500±8 days (approximately 12.33 years).It decays into helium-3 by the reaction

 31T → 32He + e− + νe

pH is defined as minus the decimal logarithm of the hydrogen ion activity in an aqueous solution. By virtue of its logarithmic nature, pH is a dimensionless quantity.

$\mathrm{pH} = - \log_{10} a_ \mbox{H} = \log_{10} \frac{1}{a_ \mbox{H}}$

where aH is the (dimensionless) activity of hydrogen ions.

Ans 2:

pT = 1.5 , therefore [T+] = 10(-1.5) = 0.032 M

Half life for Tritium is 12.33 yrs, therfore aftr 24.8 yrs , its has had two half lives, hence its conc. .is c/4 = .032/4 = .008 M  .

Now calculate the no. of moles in 600 ml. hence one can calculate the no. of moles converted from initial conc and final conc.

After this, we can see from the eq that fr one mole of Tritium decayed , one mole of Beta particle is emitted , hence we can find the no. of beta particles emitted by knowing the total moles converted.

10 Points
14 years ago

Hi

An acid dissociation constant, Ka, (also known as acidity constant, or acid-ionization constant) is a quantitative measure of the strength of an acid in solution. It is the equilibrium constant for a chemical reaction known as dissociation in the context of acid-base reactions. The equilibrium can be written symbolically as:

HA A + H+,

where HA is a generic acid which dissociates by splitting into A, known as the conjugate base of the acid, and the hydrogen ion or proton, H+, which, in the case of aqueous solutions, exists as a solvated hydronium ion. In the example shown in the figure, HA represents acetic acid, and A the acetate ion. The chemical species HA, A and H+ are said to be in equilibrium when their concentrations do not change with the passing of time. The dissociation constant is usually written as a quotient of the equilibrium concentrations, denoted by [HA], [A] and [H+]:

$K_a equals the equilibrium concentration of the deprotonated form A-, times the equilibrium concentration of H+, all divided by the equilibrium concentration of the acid AH.$
we have already calculated [T+], but we still need the conc of TF and F- , then only we can find Ka .