Arrange the following in order of increasing base strength.
`NH_(3), PH_(3), AsH_(3), SbH_(3), BiH_(3)`

Explanation

To solve the problem of arranging the given hydrides in order of increasing base strength, we will follow these steps:

### Step 1: Understand Basic Strength
Basic strength refers to the ability of a compound to donate a pair of electrons. In the case of the hydrides of group 15 elements (NH3, PH3, AsH3, SbH3, BiH3), the basic strength is influenced by the electron density on the central atom (N, P, As, Sb, Bi).

### Step 2: Analyze the Trend in Group 15
As we move down the group from nitrogen (N) to bismuth (Bi), the size of the atoms increases. This increase in atomic size leads to a decrease in electron density because the outer electrons are further away from the nucleus and are less tightly held.

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